GLES error: vertex attribute array is enabled with no data bound - android

New to OpenGl and currently working on Android NDK. I am currently getting this error, and can't figure it out. I feel like it's something basic, but I could be wrong. the appRender is run every frame by the java render side.
Error:
E/emuglGLESv2_enc: glDrawArrays: a vertex attribute array is enabled with no data bound
app.cpp:
void appRender(long tick, int width, int height){
const float vertices[] =
{
0.0f, 0.5f, 0.0f,
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f
};
glClear(GL_COLOR_BUFFER_BIT);
GLuint vertexBuffer;
glGenBuffers(1, &vertexBuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// Setup colors for each vertex
GLfloat colors[3*4];
for (int v = 0; v < 3; v++){
colors[4*v+0] = 0;
colors[4*v+1] = 1;
colors[4*v+2] = 0;
colors[4*v+3] = 1;
}
// Setup color buffer
GLuint colorBuffer;
glGenBuffers(1, &colorBuffer);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
glVertexAttribPointer(
1,
3,
GL_FLOAT,
GL_FALSE,
0,
(void*)0
);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glVertexAttribPointer(
1,
4,
GL_FLOAT,
GL_FALSE,
0,
(void*)0
);
glDrawArrays(GL_TRIANGLES, 0, 3);
glDisableVertexAttribArray(0);
glDisableVertexAttribArray(1);
glBindTexture(GL_TEXTURE_2D, 0);
//textRenderer.RenderTexts(0.5f);
//boxRenderer.RenderBoxes(0.5f);
}

So I found it, and yes, I'm bad.
glVertexAttribPointer(1,3,...) -> glVertexAttribPointer(0,3,...)

Related

I receive INVALID OPERATION when I use glBlitFramebuffer to implement MSAA

Perhaps I have some stupid problems. I'll be appreciate if someone could reply them.
All the problems are based on Android environment and OpenGL ES.
How to verified whether I has opened the MSAA or not ? If I draw some GL_POINTS with points size 50, there are some small squares. If I enabled 4x MSAA, can the small squares become round points ?
I tried my best to enable MSAA with FBO and BlitFBO. But it draw nothing and there is an error INVALID_OPERATION after glBlitFramebuffer() calling.
Here is the complete projects I mentioed above:https://github.com/Enoch-Liu/GL
And the following is the key codes:
void Renderer::MultisampleAntiAliasing() {
glGenRenderbuffers(1, &m_MSColor);
glBindRenderbuffer(GL_RENDERBUFFER, m_MSColor);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_RGBA8, m_width, m_height);
checkGLError("GenMSColorBuffer");
glGenFramebuffers(1, &m_MSFBO);
glBindFramebuffer(GL_FRAMEBUFFER, m_MSFBO);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, m_MSColor);
checkGLError("FboRbo,COLORATTACHMENT");
glGenRenderbuffers(1, &m_MSDepth);
glBindRenderbuffer(GL_RENDERBUFFER, m_MSDepth);
glRenderbufferStorageMultisample(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, m_width, m_height);
checkGLError("GenDepthBuffer");
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_MSDepth);
checkGLError("DepthBuffer,Renderbuffer");
GLenum drawBufs[] = {GL_COLOR_ATTACHMENT0};
glDrawBuffers(1, drawBufs);
checkGLError("DrawBuffer");
if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
LOG_ERROR("failed to make complete framebuffer object %x", glCheckFramebufferStatus(GL_FRAMEBUFFER));
}
}
void Renderer::drawFrame() {
//LOG_INFO("drawFrame %d x %d", width, height);
static float r=0.9f;
static float g=0.2f;
static float b=0.2f;
LOG_INFO("xxx %d, %d", m_width,m_height);
if (OPENMSAA)
{
glBindFramebuffer(GL_FRAMEBUFFER, m_MSFBO);
glBindRenderbuffer(GL_RENDERBUFFER, m_MSColor);
checkGLError("BindTwoBuffers");
}
glViewport(0,0,m_width,m_height);
glScissor(0,0,m_width,m_height);
glClearColor(r, g, b, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glDisable(GL_DEPTH_TEST);
const GLfloat landscapeOrientationMatrix[16] = {
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat color[4] = {
1.0f, 0.0f, 0.0f, 1.0f
};
glUseProgram( m_program );
glUniformMatrix4fv(m_uMvp, 1, GL_FALSE, landscapeOrientationMatrix);
glUniform4fv(m_uColor, 1, color);
m_p = glGetAttribLocation(m_program, "vPosition");
m_p1 = glGetAttribLocation(m_program, "vPosition1");
glEnableVertexAttribArray( m_p );
glVertexAttribPointer( m_p , 3, GL_FLOAT, false, 3 * sizeof( float ), squareCoords);
glDrawArrays(GL_POINTS, 0, 4);
glDisableVertexAttribArray( m_p );
glFlush();
checkGLError("Before Blit");
if (OPENMSAA)
{
glBindFramebuffer(GL_READ_FRAMEBUFFER, m_MSFBO);
checkGLError("BindReadBuffer");
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
checkGLError("BindFramebuffer");
glBlitFramebuffer(0, 0, m_width, m_height, 0, 0, m_width, m_height, GL_COLOR_BUFFER_BIT, GL_NEAREST);
checkGLError("BlitFramebufferColor");
glBlitFramebuffer(0, 0, m_width, m_height, 0, 0, m_width, m_height, GL_DEPTH_BUFFER_BIT, GL_NEAREST);
checkGLError("BlitFramebufferDepth");
glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
}
}
The framebuffer is complete.
The internal format of the depth buffers have to match: https://www.opengl.org/discussion_boards/showthread.php/173275-Alternative-to-glBlitFramebuffer%28%29
Looking at your github project you are not configuring a depth buffer at all. From your project:
const EGLint attribs[] = {
// EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
EGL_BLUE_SIZE, 8,
EGL_GREEN_SIZE, 8,
EGL_RED_SIZE, 8,
EGL_ALPHA_SIZE, 8,
EGL_SAMPLE_BUFFERS, 1,
EGL_SAMPLES, 4,
EGL_NONE
};

Opengles 2.0 without VAO

I was going along just fine working on an opengles 2.0 application until I tested it on an older phone that doesn't support VAO and now I seem to have fallen into a marsh.
I started using opengl after VAO's were sorta standard and everywhere so I never had to render without using one. Now that I have to write code that supports it I am having some trouble.
vertex shader
attribute vec3 position;
attribute vec4 icolor;
varying vec4 fcolor;
void main()
{
gl_Position = vec4(position, 1.0);
fcolor = icolor;
}
fragment shader
precision mediump float;
varying vec4 fcolor;
void main (void)
{
gl_FragColor = fcolor;
}
application side of things
init code:
glGenBuffers(1, &verticesBuffer);
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->vertices), rend2d->vertices, GL_STATIC_DRAW);
glGenBuffers(1, &indicesBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(rend2d->indices), rend2d->indices, GL_STATIC_DRAW);
glGenBuffers(1, &colorBuffer);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->colors), rend2d->colors, GL_STATIC_DRAW);
rendering code:
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(sp);
GLint posLoc = glGetAttribLocation(sp, "position");
GLint colLoc = glGetAttribLocation(sp, "icolor");
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glVertexAttribPointer(colLoc, 4, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer);
glDrawElements(GL_TRIANGLES, rend2d->vertexCount, GL_UNSIGNED_INT, 0);
my error might be glaringly obvious but I just don't see what part I am currently not doing correctly and hoping to get some help with semi-modern opengl. This is mainly to provide support for apps that are opengles 2.0 but do not support the
GL_OES_vertex_array_object extension.
I wanted to post the answer because it was many little things that were wrong. First I'll post the data structure that I was using to hold my gl data.
typedef struct
{
GLuint vertexCount;
GLfloat vertices[12];
GLfloat colors[16];
GLuint indices[6];
GLfloat texCoords[8];
} renderable2d;
the first problem was here. As #derhass pointed out on the irc channel opengles 2.0 doesn't support 32bit indices. So the first step was to change that gluint above to glushort
typedef struct
{
GLushort vertexCount; //I made this a short as well
GLfloat vertices[12];
GLfloat colors[16];
GLushort indices[6]; //make this a short instead of an int
GLfloat texCoords[8];
}
once that part was fixed, then I had to generate my buffers, bind them and put the data in them, then unbind.
//bind n setup vertices
glGenBuffers(1, &verticesBuffer);
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->vertices), rend2d->vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
//bind n setup colors
glGenBuffers(1, &colorBuffer);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->colors), rend2d->colors, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
//bind n setup indices
glGenBuffers(1, &indicesBuffer);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(rend2d->indices), rend2d->indices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
and finally on to the rendering code
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(sp);
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glEnableVertexAttribArray(posLoc);
glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glEnableVertexAttribArray(colLoc);
glVertexAttribPointer(colLoc, 4, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indicesBuffer);
glDrawElements(GL_TRIANGLES, rend2d->vertexCount, GL_UNSIGNED_SHORT, 0);
after doing all that I got things sorted out on both devices. Just for clarity rend2d is just a textured quad so rend2d->vertexCount = 6; With more complex models well you'll get that info somewhere else.
1) GL_UNSIGNED_INT is not officially supported in ES 2.0 as an index type
your GL_UNSIGNED_INT must be either one GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT
2) Assume they are friends when you use VBO without VAO.
glBindBuffer();
glVertexAttribPointer();
glEnableVertexAttribArray(); // you don't call it
In init()
GLint posLoc = glGetAttribLocation(sp, "position");
GLint colLoc = glGetAttribLocation(sp, "icolor");
glGenBuffers(1, &verticesBuffer);
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->vertices), rend2d->vertices, GL_STATIC_DRAW);
glEnableVertexAttribArray(posLoc);
glVertexAttribPointer(posLoc, GL_FLOAT,0,0,0);
glGenBuffers(1, &colorBuffer);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glBufferData(GL_ARRAY_BUFFER, sizeof(rend2d->colors), rend2d->colors, GL_STATIC_DRAW);
glEnableVertexAttribArray(colLoc)
glVertexAttribPointer(colLoc, GL_FLOAT,0,0,0);
In rendering()
glBindBuffer(GL_ARRAY_BUFFER, verticesBuffer);
glEnableVertexAttribArray(posLoc);
glVertexAttribPointer(posLoc, GL_FLOAT,0,0,0);
glBindBuffer(GL_ARRAY_BUFFER, colorBuffer);
glEnableVertexAttribArray(colLoc)
glVertexAttribPointer(colLoc, GL_FLOAT,0,0,0);
3) Just don't use VAOs in ES 2.0 in which, VAO is not officially supported. However, IOS does as an exception.

How to use VAOs in OpenGL ES 2.0

I've read that using VAOs is recommended but I don't know how.
I am using the tegra android development pack (which uses OpenGL ES 2.0) and I can't find the methodes glGenVertexArrays and glBindVertexArray. Are VAOs supported in ES 2.0 (without extensions)?
Also I don't understand what the benefit of a VAO is. Currently I compile the shaders and use glBindAttribLocation. After that I define the vertex positions and colors for a triangle and use glVertexAttribPointer. Then I just draw the triangle again and again.
This is the program (without error checks):
static void createProgram() {
// vertex shader
const char* vertexShaderCode = getVertexShaderCode();
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderCode, NULL);
glCompileShader(vertexShader);
// fragment shader
const char* fragmentShaderCode = getFragmentShaderCode();
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderCode, NULL);
glCompileShader(fragmentShader);
// create program
program = glCreateProgram();
glAttachShader(program, vertexShader);
glAttachShader(program, fragmentShader);
// Dem Programm sagen, unter welchem Index die Daten der Shader Attribute liegen
glBindAttribLocation(program, 1, "in_pos");
glBindAttribLocation(program, 2, "in_color");
glLinkProgram(program);
}
And this is the triangle:
static void loadGeometry() {
GLuint buffers[2];
glGenBuffers(2, buffers);
GLuint vboPosition = buffers[0];
GLuint vboColor = buffers[1];
const int VERTEX_POSITION_BUFFER_SIZE = 12;
const int VERTEX_POSITION_BUFFER_BYTESIZE = sizeof(GLfloat)* VERTEX_POSITION_BUFFER_SIZE;
GLfloat vertexPositionBuffer[VERTEX_POSITION_BUFFER_SIZE] = {
0.0f, 0.5f, 0.0f, 1.0f,
-0.5f, -0.5f, 0.0f, 1.0f,
0.5f, -0.5f, 0.0f, 1.0f };
glBindBuffer(GL_ARRAY_BUFFER, vboPosition);
glBufferData(GL_ARRAY_BUFFER, VERTEX_POSITION_BUFFER_BYTESIZE, vertexPositionBuffer, GL_STATIC_DRAW);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, 0);
// Repeat for color...
}
And in the draw call I just do
glUseProgram(program);
glDrawArrays(GL_TRIANGLES, 0, 3);

Fatal signal on glDrawArrays within onDrawFrame (GLSurfaceView.Renderer, SurfaceTexture.OnFrameAvailableListener)

I am getting a Fatal Signal 11 after quite a few
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
calls within my OnDrawFrame function. The textures are been drawn correctly before the crash, which I believe it means that my vertex and fragment shaders work fine.
What I am trying to do, is to blend two textures together using GLSurfaceView.Renderer and SurfaceTexture.OnFrameAvailableListener.
The first texture is a live camera preview SurfaceTexture which works fine by its own. The second tetxure is just a bitmap image, which also works fine by its own. but combining them gives the crash.
My OnDrawFrame is as follows:
public void onDrawFrame(GL10 glUnused) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
synchronized(this) {
if (updateSurface) {
mSurface.updateTexImage();
mSurface.getTransformMatrix(mSTMatrix);
updateSurface = false;
}
}
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
muSTMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uSTMatrix");
muCRatioHandle = GLES20.glGetUniformLocation(mProgram, "uCRatio");
GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, textures[0]);
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
int t1h = GLES20.glGetUniformLocation ( mProgram, "sTexture1" );
// GLES20.glUniform1i(t1h, textures[0]);
GLES20.glUniform1i(t1h, 1);
GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, textures[1]);
GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
int t2h = GLES20.glGetUniformLocation ( mProgram, "sTexture2" );
GLES20.glUniform1i(t2h, 2);
GLES20.glUseProgram(mProgram);
GLES20.glEnable(GLES20.GL_BLEND);
GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
mTriangleVertices.position(0);
GLES20.glEnableVertexAttribArray(maPositionHandle);
GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
4*5, mTriangleVertices);
mTriangleVertices.position(3);
GLES20.glEnableVertexAttribArray(maTextureHandle);
GLES20.glVertexAttribPointer(maTextureHandle, 3, GLES20.GL_FLOAT, false,
4*5, mTriangleVertices);
Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, mMMatrix, 0);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0);
GLES20.glUniform1f(muCRatioHandle, mCameraRatio);
GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0);
GLES20.glBindBuffer(GLES20.GL_ELEMENT_ARRAY_BUFFER, 0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
GLES20.glDisableVertexAttribArray(maPositionHandle);
GLES20.glDisableVertexAttribArray(maTextureHandle);
// GLES20.glFlush();
}
where mTriangleVertices is:
mTriangleVertices = ByteBuffer.allocateDirect(mTriangleVerticesData.length
* FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangleVertices.put(mTriangleVerticesData).position(0);
and mTriangleVerticesData is:
private final float[] mTriangleVerticesData = {
// X, Y, Z, U, V
-1.0f, -1.0f, 0, 0.f, 0.f,
1.0f, -1.0f, 0, 1.f, 0.f,
-1.0f, 1.0f, 0, 0.f, 1.f,
1.0f, 1.0f, 0, 1.f, 1.f,
};
Any tips, links or even code snippets would be much appreciated!
Thank you in advance
Don't know if this is the cause for the crash but you're assigning one too high texture ids for shader at least. For example;
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
int t1h = GLES20.glGetUniformLocation ( mProgram, "sTexture1" );
GLES20.glUniform1i(t1h, 1);
Should read
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
int t1h = GLES20.glGetUniformLocation ( mProgram, "sTexture1" );
GLES20.glUniform1i(t1h, 0);
Edit: Ah, this might be the cause for the crash:
GLES20.glVertexAttribPointer(maTextureHandle, 3, GLES20.GL_FLOAT, false,
4*5, mTriangleVertices);
It should be
GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
4*5, mTriangleVertices);
More likely since you have two texture values per vertex.

OpenGL ES - texture map all faces of an 8 vertex cube?

Working through some OpenGL-ES tutorials, using the Android emulator. I've gotten up to texture mapping and am having some trouble mapping to a cube. Is it possible to map a texture to all faces of a cube that has 8 vertices and 12 triangles for the 6 faces as described below?
// Use half as we are going for a 0,0,0 centre.
width /= 2;
height /= 2;
depth /= 2;
float vertices[] = { -width, -height, depth, // 0
width, -height, depth, // 1
width, height, depth, // 2
-width, height, depth, // 3
-width, -height, -depth, // 4
width, -height, -depth, // 5
width, height, -depth, // 6
-width, height, -depth, // 7
};
short indices[] = {
// Front
0,1,2,
0,2,3,
// Back
5,4,7,
5,7,6,
// Left
4,0,3,
4,3,7,
// Right
1,5,6,
1,6,2,
// Top
3,2,6,
3,6,7,
// Bottom
4,5,1,
4,1,0,
};
float texCoords[] = {
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f,
};
I have gotten the front and back faces working correctly, however, none of the other faces are showing the texture.
Drawing code
public void draw(GL10 gl) {
// Counter-clockwise winding.
gl.glFrontFace(GL10.GL_CCW);
// Enable face culling.
gl.glEnable(GL10.GL_CULL_FACE);
// What faces to remove with the face culling.
gl.glCullFace(GL10.GL_BACK);
// Enabled the vertices buffer for writing and to be used during
// rendering.
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
// Specifies the location and data format of an array of vertex
// coordinates to use when rendering.
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, verticesBuffer);
if (normalsBuffer != null) {
// Enabled the normal buffer for writing and to be used during rendering.
gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
// Specifies the location and data format of an array of normals to use when rendering.
gl.glNormalPointer(GL10.GL_FLOAT, 0, normalsBuffer);
}
// Set flat color
gl.glColor4f(rgba[0], rgba[1], rgba[2], rgba[3]);
// Smooth color
if ( colorBuffer != null ) {
// Enable the color array buffer to be used during rendering.
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
// Point out the where the color buffer is.
gl.glColorPointer(4, GL10.GL_FLOAT, 0, colorBuffer);
}
// Use textures?
if ( textureBuffer != null) {
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
}
// Translation and rotation before drawing
gl.glTranslatef(x, y, z);
gl.glRotatef(rx, 1, 0, 0);
gl.glRotatef(ry, 0, 1, 0);
gl.glRotatef(rz, 0, 0, 1);
gl.glDrawElements(GL10.GL_TRIANGLES, numOfIndices, GL10.GL_UNSIGNED_SHORT, indicesBuffer);
// Disable the vertices buffer.
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
gl.glDisableClientState(GL10.GL_NORMAL_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// Disable face culling.
gl.glDisable(GL10.GL_CULL_FACE);
}
You have to use 24 vertexes. In OpenGL, a vertex is more than just position, it is the collection of all vertex attributes. Every vertex array is accessed with the same index.
The infamous cube example is something almost everyone feels is inefficient when starting to use OpenGL, but in real-world, more complex models, the degree of duplication is quite low.
I have "only" modified the GLES20TriangleRenderer.java file into the SDK example BasicGLSurfaceView, compile it and test it on two Android devices, an Android Phone and a Nexus 7 and this work good on the two devices :)
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
Modified by YLP (06 January 2014) for to handle a rotated texture mapped cube
*/
package com.example.android.basicglsurfaceview;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.GLUtils;
import android.opengl.Matrix;
import android.os.SystemClock;
import android.util.Log;
class GLES20TriangleRenderer implements GLSurfaceView.Renderer {
public GLES20TriangleRenderer(Context context) {
mContext = context;
// mTriangleVertices = ByteBuffer.allocateDirect(mTriangleVerticesData.length * FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer();
// mTriangleVertices.put(mTriangleVerticesData).position(0);
mTriangleVertices = ByteBuffer.allocateDirect(cubeVerticesStrip.length * FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangleVertices.put(cubeVerticesStrip).position(0);
mTriangleTexcoords = ByteBuffer.allocateDirect(cubeTexCoordsStrip.length * FLOAT_SIZE_BYTES).order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangleTexcoords.put(cubeTexCoordsStrip).position(0);
}
public void onDrawFrame(GL10 glUnused) {
// Ignore the passed-in GL10 interface, and use the GLES20
// class's static methods instead.
GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
GLES20.glClear( GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glEnable( GLES20.GL_DEPTH_TEST );
GLES20.glDepthFunc( GLES20.GL_LEQUAL );
GLES20.glDepthMask( true );
GLES20.glUseProgram(mProgram);
checkGlError("glUseProgram");
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureID);
// mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
// GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
// TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
// checkGlError("glVertexAttribPointer maPosition");
// mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
// GLES20.glEnableVertexAttribArray(maPositionHandle);
// checkGlError("glEnableVertexAttribArray maPositionHandle");
// GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
// TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
// checkGlError("glVertexAttribPointer maTextureHandle");
// GLES20.glEnableVertexAttribArray(maTextureHandle);
// checkGlError("glEnableVertexAttribArray maTextureHandle");
// From http://www.endodigital.com/opengl-es-2-0-on-the-iphone/part-fourteen-creating-the-cube
// (but slighty modified)
mTriangleVertices.position(0);
// GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false, TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false, 0, mTriangleVertices);
GLES20.glEnableVertexAttribArray(maPositionHandle);
mTriangleTexcoords.position(0);
// GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false, 0, mTriangleTexcoords);
GLES20.glEnableVertexAttribArray(maTextureHandle);
long time = SystemClock.uptimeMillis() % 4000L;
float angle = 0.090f * ((int) time);
float scale = 0.7f;
Matrix.setRotateM(mMMatrix, 0, angle, 0, 0, 1.0f);
// YLP : add others movements cycles
Matrix.rotateM(mMMatrix, 0, angle, 1.0f, 0.0f, 0.0f );
// Matrix.rotateM(mMMatrix, 0, angle, 0.0f, 1.0f, 0.0f );
// float scale = (float)( Math.abs( Math.sin( ((float)time) * (6.28f/4000.0f) ) ));
Matrix.scaleM(mMMatrix, 0, scale, scale, scale);
Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, mMMatrix, 0);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
// Somes tests with only somes triangles
// GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 3); // worked initialy but only one triangle
// GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 6); // worked initialy but only two triangles
// GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4); // GL_QUADS does not exist in GL 2.0 :(
// GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 8); // GL_QUADS does not exist in GL 2.0 :(
// Draw the cube
// TODO : make only one glDraWArrays() call instead one per face
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 4, 4);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 8, 4);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 12, 4);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 16, 4);
GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 20, 4);
checkGlError("glDrawArrays");
}
public void onSurfaceChanged(GL10 glUnused, int width, int height) {
// Ignore the passed-in GL10 interface, and use the GLES20
// class's static methods instead.
GLES20.glViewport(0, 0, width, height);
float ratio = (float) width / height;
Matrix.frustumM(mProjMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
}
public void onSurfaceCreated(GL10 glUnused, EGLConfig config) {
// Ignore the passed-in GL10 interface, and use the GLES20
// class's static methods instead.
mProgram = createProgram(mVertexShader, mFragmentShader);
if (mProgram == 0) {
return;
}
maPositionHandle = GLES20.glGetAttribLocation(mProgram, "aPosition");
checkGlError("glGetAttribLocation aPosition");
if (maPositionHandle == -1) {
throw new RuntimeException("Could not get attrib location for aPosition");
}
maTextureHandle = GLES20.glGetAttribLocation(mProgram, "aTextureCoord");
checkGlError("glGetAttribLocation aTextureCoord");
if (maTextureHandle == -1) {
throw new RuntimeException("Could not get attrib location for aTextureCoord");
}
muMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
checkGlError("glGetUniformLocation uMVPMatrix");
if (muMVPMatrixHandle == -1) {
throw new RuntimeException("Could not get attrib location for uMVPMatrix");
}
/*
* Create our texture. This has to be done each time the
* surface is created.
*/
int[] textures = new int[1];
GLES20.glGenTextures(1, textures, 0);
mTextureID = textures[0];
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureID);
GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER,
GLES20.GL_NEAREST);
GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D,
GLES20.GL_TEXTURE_MAG_FILTER,
GLES20.GL_LINEAR);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S,
GLES20.GL_REPEAT);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T,
GLES20.GL_REPEAT);
InputStream is = mContext.getResources()
.openRawResource(R.raw.robot);
Bitmap bitmap;
try {
bitmap = BitmapFactory.decodeStream(is);
} finally {
try {
is.close();
} catch(IOException e) {
// Ignore.
}
}
GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
Matrix.setLookAtM(mVMatrix, 0, 0, 0, -5, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
}
private int loadShader(int shaderType, String source) {
int shader = GLES20.glCreateShader(shaderType);
if (shader != 0) {
GLES20.glShaderSource(shader, source);
GLES20.glCompileShader(shader);
int[] compiled = new int[1];
GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
if (compiled[0] == 0) {
Log.e(TAG, "Could not compile shader " + shaderType + ":");
Log.e(TAG, GLES20.glGetShaderInfoLog(shader));
GLES20.glDeleteShader(shader);
shader = 0;
}
}
return shader;
}
private int createProgram(String vertexSource, String fragmentSource) {
int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
if (vertexShader == 0) {
return 0;
}
int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
if (pixelShader == 0) {
return 0;
}
int program = GLES20.glCreateProgram();
if (program != 0) {
GLES20.glAttachShader(program, vertexShader);
checkGlError("glAttachShader");
GLES20.glAttachShader(program, pixelShader);
checkGlError("glAttachShader");
GLES20.glLinkProgram(program);
int[] linkStatus = new int[1];
GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus, 0);
if (linkStatus[0] != GLES20.GL_TRUE) {
Log.e(TAG, "Could not link program: ");
Log.e(TAG, GLES20.glGetProgramInfoLog(program));
GLES20.glDeleteProgram(program);
program = 0;
}
}
return program;
}
private void checkGlError(String op) {
int error;
while ((error = GLES20.glGetError()) != GLES20.GL_NO_ERROR) {
Log.e(TAG, op + ": glError " + error);
throw new RuntimeException(op + ": glError " + error);
}
}
private static final int FLOAT_SIZE_BYTES = 4;
private static final int TRIANGLE_VERTICES_DATA_STRIDE_BYTES = 5 * FLOAT_SIZE_BYTES;
private static final int TRIANGLE_VERTICES_DATA_POS_OFFSET = 0;
private static final int TRIANGLE_VERTICES_DATA_UV_OFFSET = 3;
private static final int TRIANGLE_TEXCOORDS_DATA_STRIDE_BYTES = 2 * FLOAT_SIZE_BYTES;
private final float[] mTriangleVerticesData =
{
// X, Y, Z, U, V
// initial triangle from the source
// -1.0f, -0.5f, 0, -0.5f, 0.0f,
// 1.0f, -0.5f, 0, 1.5f, -0.0f,
// 0.0f, 1.11803399f, 0, 0.5f, 1.61803399f,
// YLP : transform this to two triangles for to have a quad
// -1, -1, 0, 0, 0,
// 1, -1, 0, 1, 0,
// -1, 1, 0, 0, 1,
// 1, 1, 0, 1, 1,
// -1, 1, 0, 0, 1,
// 1, -1, 0, 1, 0
// YLP : use two quads with GL_TRIANGLE_STRIP
// Don't work because this make one accordeon effect :(
-1, -1, -1, 0, 0,
1, -1, -1, 1, 0,
-1, 1, -1, 0, 1,
1, 1, -1, 1, 1,
-1, -1, 1, 0, 0,
1, -1, 1, 1, 0,
-1, 1, 1, 0, 1,
1, 1, 1, 1, 1,
};
// From http://www.endodigital.com/opengl-es-2-0-on-the-iphone/part-fourteen-creating-the-cube/
// (only moodify "static const GLfloat" to "private final float" on it)
private final float cubeVerticesStrip[] = {
// Front face
-1,-1,1, 1,-1,1, -1,1,1, 1,1,1,
// Right face
1,-1,1, 1,-1,-1, 1,1,1, 1,1,-1,
// Back face
1,-1,-1, -1,-1,-1, 1,1,-1, -1,1,-1,
// Left face
-1,-1,-1, -1,-1,1, -1,1,-1, -1,1,1,
// Bottom face
-1,-1,-1, 1,-1,-1, -1,-1,1, 1,-1,1,
// Top face
-1,1,1, 1,1,1, -1,1,-1, 1,1,-1
};
private final float cubeTexCoordsStrip[] = {
// Front face
0,0, 1,0, 0,1, 1,1,
// Right face
0,0, 1,0, 0,1, 1,1,
// Back face
0,0, 1,0, 0,1, 1,1,
// Left face
0,0, 1,0, 0,1, 1,1,
// Bottom face
0,0, 1,0, 0,1, 1,1,
// Top face
0,0, 1,0, 0,1, 1,1
};
private FloatBuffer mTriangleVertices;
private FloatBuffer mTriangleTexcoords;
private final String mVertexShader =
"uniform mat4 uMVPMatrix;\n" +
"attribute vec4 aPosition;\n" +
"attribute vec2 aTextureCoord;\n" +
"varying vec2 vTextureCoord;\n" +
"void main() {\n" +
" gl_Position = uMVPMatrix * aPosition;\n" +
" vTextureCoord = aTextureCoord;\n" +
"}\n";
private final String mFragmentShader =
"precision mediump float;\n" +
"varying vec2 vTextureCoord;\n" +
"uniform sampler2D sTexture;\n" +
"void main() {\n" +
" gl_FragColor = texture2D(sTexture, vTextureCoord);\n" +
"}\n";
private float[] mMVPMatrix = new float[16];
private float[] mProjMatrix = new float[16];
private float[] mMMatrix = new float[16];
private float[] mVMatrix = new float[16];
private float[] mMMatrix2 = new float[16];
private int mProgram;
private int mTextureID;
private int muMVPMatrixHandle;
private int maPositionHandle;
private int maTextureHandle;
private Context mContext;
private static String TAG = "GLES20TriangleRenderer";
}
=> I managed to implement this in just a few hours and this work :)
==> so if Android is not the best platform, this seem however a really good and viable plateform for that I begin to play a little more with some multimédia developments on Android's devices :)

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