OpenGL ES 2.0 Not rendering correctly - android

This is supposed to render a cube. It looks like some parts of the rear faces are rendering in front of the ones closest to the camera. This happens even if I set it farther away. This is from my renderer:
public void onDrawFrame(GL10 unused) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
// Set the camera position
Matrix.setLookAtM(mVMatrix, 0, 0, 0, -3f, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
Matrix.setIdentityM(mModelMatrix, 0);
Matrix.setRotateM(mModelMatrix, 0, mAngle, 0f, 1f, 0.0f);
Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, mModelMatrix, 0);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);
// Draw object
cube.draw(mMVPMatrix, context);
mAngle++;
}
and my object's draw method
public void draw(float[] mvpMatrix, Context context) {
GLES20.glUseProgram(mProgram);
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
GLES20.glVertexAttribPointer(mTexHandle, 2,
GLES20.GL_FLOAT, false,
8, textureBuffer);
GLES20.glEnableVertexAttribArray(mPositionHandle);
GLES20.glEnableVertexAttribArray(mTexHandle);
GLES20.glActiveTexture ( GLES20.GL_TEXTURE0 );
GLES20.glBindTexture ( GLES20.GL_TEXTURE_2D, mTextureID);
GLES20.glUniform1i ( mSampler, 0 );
mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
GLES20.glDisableVertexAttribArray(mPositionHandle);
GLES20.glDisableVertexAttribArray(mTexHandle);
}
and my shaders:
String vertexShaderCode =
"uniform mat4 uMVPMatrix;" +
"uniform float u_offset; \n" +
"attribute vec4 a_position; \n" +
"attribute vec2 a_texCoord; \n" +
"varying vec2 v_texCoord; \n" +
"void main() \n" +
"{ \n" +
" gl_Position = uMVPMatrix * a_position; \n" +
" gl_Position.x += u_offset;\n" +
" v_texCoord = a_texCoord; \n" +
"} \n";
String fragmentShaderCode =
"precision mediump float; \n" +
"varying vec2 v_texCoord; \n" +
"uniform sampler2D s_texture; \n" +
"void main() \n" +
"{ \n" +
" gl_FragColor = texture2D(s_texture, v_texCoord); \n" +
"} \n";
and the result
Picture:
http://i.imgur.com/eWI2Uom.png
Thanks

Assuming you're using the depth buffer, you don't seem to be clearing it in your onDrawFrame function. Try:
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT|GLES20.GL_DEPTH_BUFFER_BIT);

I'm not sure about Android-specific code as I program on iOS, but it's my understanding from reading "OpenGL ES 2.0 Programming Guide" (by Munshi et al.) that very little differs. Here's what my code looks like from a recent small project:
After setting up your framebuffer and color-renderbuffer, as you've already done, set up the depth buffer.
GLuint depthRenderbuffer;
GLint backingWidth, backingHeight;
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_WIDTH, &backingWidth);
glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_HEIGHT, &backingHeight);
glGenRenderbuffers(1, &depthRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, depthRenderbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, backingWidth, backingHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderbuffer);
It's a good idea to include the part about setting the depthbuffer dimensions based off the color-renderbuffer, using glGetRenderbufferParameteriv(), because it ensures that no matter what, they're going to match.
One side note, on iOS it's recommended to setup the color-renderbuffer storage directly from the underlying iOS drawing layer, however in setting up the depth-renderbuffer it requires the call to glRenderbufferStorage() instead, as I've shown above.
You'll also want to include the following lines of code to your draw routine:
glClearDepthf(1.0);
glEnable(GL_DEPTH_TEST);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
If you don't make the call to glEnable(GL_DEPTH_TEST), it seems to glitch at first and then work just fine, at least on my implementation in iOS. The glClearDepthf(1.0) clears it all the way to the far-plane, as opposed to a value of 0.0 which clears it to the front-plane.
It looks like you may have some Android-specific code, but hopefully this gets you off to the right start. Cheers!

Related

Android/OpenGles drawing 2 external texture each taking half of the screen. Left and right half

I have successfully bind 2 external OES texture to my shader. Now I want each texture to take 1/2 of the screen(Left for one texture right for another). How do I go about doing it? Example:
http://vicceskep.hu/kepek/vicces_funny_007445.jpg
random image from google
Showing a full picture of each picture. It will be nice to have an efficient method to do it. The code that I am currently referencing from is the bikflake/ grafika code from github.
Visit http://bigflake.com/mediacodec/CameraToMpegTest.java.txt
To check the code out.
Okay I think i will really give in depth clarification for my question as I do not have much knowledge about 3d projections in open GL. Sorry for the numerous edits on the question.
This is my Vertex Shader code currently
private static final String VERTEX_SHADER =
// UMVPMATRIX IS AN IDENTITY MATRIX
"uniform mat4 uMVPMatrix;\n" +
//These are surfacetexture.getTransformationMatrix
"uniform mat4 uSTMatrixOne;\n" +
"uniform mat4 uSTMatrixTwo;\n" +
"attribute vec4 aPosition;\n" +
"attribute vec4 aTextureCoord;\n" +
"varying vec2 vTextureCoord;\n" +
"varying vec2 vTextureCoordTwo;\n" +
"void main() {\n" +
" gl_Position = uMVPMatrix * aPosition;\n" +
" vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" +
" vTextureCoordTwo = (uSTMatrixTwo* aTextureCoord).xy ;\n" +
"}\n";
This is my Fragment Shader code currently which does a overlay currently.
private static final String FRAGMENT_SHADER =
"#extension GL_OES_EGL_image_external : require\n" +
"precision mediump float;\n" + // highp here doesn't seem to matter
"varying vec2 vTextureCoord;\n" +
"varying vec2 vTextureCoordTwo;\n" +
"uniform samplerExternalOES sTextureOne;\n" +
"uniform samplerExternalOES sTextureTwo;\n" +
"void main() {\n" +
" lowp vec4 pixelTop = texture2D(sTextureOne, vTextureCoord);\n" +
" lowp vec4 pixelBot = texture2D(sTextureTwo, vTextureCoordTwo);" +
" gl_FragColor = pixelTop + pixelBot;\n" +
"}\n";
As for the aPosition and the a texture coordinate it is currently referenced from. It would be nice if someone explained how mTraingleVerticesData works too.
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,
};
GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false,
TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
checkGlError("glVertexAttribPointer maPosition");
GLES20.glEnableVertexAttribArray(maPositionHandle);
checkGlError("glEnableVertexAttribArray maPositionHandle");
mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
GLES20.glVertexAttribPointer(maTextureHandle, 2, GLES20.GL_FLOAT, false,
TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices);
My 2 external projection binding currently
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID);
//Cam Code
//Set texture to be active
GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTwoTextureID);
You can do it the way #Sung suggested but conditional statements and loops in shaders, especialy fragment, are slow. It's better to render 2 different polygons.
Yea I finally got it.I used 2 different programs to draw and used mTriangleVerticesData to edit the image proportions and use gl_position to shift the image.

combine surface texture(external basically camera feed ) and ordinary texture

i am trying to combine surface texture(external basically camera feed ) and ordinary texture , when i run this the screen becomes black i tried in galaxy s5,s6 got the same results,searched online but couldn't find any resources for this,Any feedback is welcome.
shaders
private final String vertexShaderCodeCamera ="uniform mat4 uMVPMatrix;" +
"attribute vec4 position;" +
"attribute vec2 inputTextureCoordinate;" +
"varying vec2 textureCoordinate;" +
"attribute vec3 a_normal;"+ //new line
"varying vec3 v_normal;"+//new line
"uniform mat4 u_MVMatrix;" +
"void main()" +
"{" +
" gl_Position = uMVPMatrix * position;" +
"textureCoordinate = inputTextureCoordinate;" +
"v_normal = vec3(u_MVMatrix * vec4(a_normal, 0.0));"+
"}";
private final String fragmentShaderCodeCamera =
"#extension GL_OES_EGL_image_external : require\n" +
"precision mediump float;" +
"varying vec2 textureCoordinate; \n" +
"uniform samplerExternalOES s_texture; \n" +
"uniform sampler2D Texture;" +
"void main(void) {" +
"gl_FragColor = texture2D(s_texture, textureCoordinate );\n" +
"gl_FragColor = texture2D(Texture, textureCoordinate);" +
"}";
camera draw method:
public void display_Camera(int texture){
GLES20.glUseProgram(cam_mProgram);
GLES20.glActiveTexture(GL_TEXTURE_EXTERNAL_OES);
GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture);
cam_mPositionHandle = GLES20.glGetAttribLocation(cam_mProgram, "position");
GLES20.glEnableVertexAttribArray(cam_mPositionHandle);
GLES20.glVertexAttribPointer(cam_mPositionHandle, CAM_COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStrideSquare, vertexBuffer);
cam_mTextureCoordHandle = GLES20.glGetAttribLocation(cam_mProgram, "inputTextureCoordinate");
GLES20.glEnableVertexAttribArray(cam_mTextureCoordHandle);
GLES20.glVertexAttribPointer(cam_mTextureCoordHandle, CAM_COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStrideSquare, textureVerticesBuffer);
cam_mColorHandle = 2;//GLES20.glGetAttribLocation(cam_mProgram, "s_texture");
GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
// Disable vertex array
GLES20.glDisableVertexAttribArray(cam_mPositionHandle);
GLES20.glDisableVertexAttribArray(cam_mTextureCoordHandle);
}
model draw method:
public void draw1(float[] mvpMatrix) {
// Add program to OpenGL environment
GLES20.glUseProgram(cam_mProgram);
// get handle to shape's transformation matrix
mPositionHandle = 0;//GLES20.glGetAttribLocation(cam_mProgram, "vPosition");
// get handle to vertex shader's vPosition member
mMVPMatrixHandle = GLES20.glGetUniformLocation(cam_mProgram, "uMVPMatrix");
MainActivity.checkGLError("glGetUniformLocation");
fsTexture = GLES20.glGetUniformLocation(cam_mProgram, "Texture");
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[0]);
GLES20.glUniform1i(fsTexture, 0);
vsTextureCoord = 1;//GLES20.glGetAttribLocation(cam_mProgram, "texCoord");
mNormalHandle = 3;//GLES20.glGetAttribLocation(cam_mProgram, "a_normal");//new line
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer(
mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
GLES20.glVertexAttribPointer(vsTextureCoord, COORDS_PER_TEXTURE,
GLES20.GL_FLOAT, false,
TextureStride, texBuffer);
GLES20.glEnableVertexAttribArray(vsTextureCoord);
GLES20.glVertexAttribPointer(mNormalHandle, COORDS_PER_NORMAL, GLES20.GL_FLOAT, false,
12, normalbuffer);//new line
GLES20.glEnableVertexAttribArray(mNormalHandle);//new line
// Apply the projection and view transformation
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
MainActivity.checkGLError("glUniformMatrix4fv");
// Draw the triangle
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, tablelamp21NumVerts);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
GLES20.glDisableVertexAttribArray(vsTextureCoord);
GLES20.glDisableVertexAttribArray(mNormalHandle);
}
linking of shaders:
cam_mProgram = GLES20.glCreateProgram(); // create empty OpenGL Program
if (cam_mProgram != 0)
{
// Bind the vertex shader to the program.
GLES20.glAttachShader(cam_mProgram, cameravertexShader);
// Bind the fragment shader to the program.
GLES20.glAttachShader(cam_mProgram, camerafragmentShader);
// Bind attributes
GLES20.glBindAttribLocation(cam_mProgram, 0, "position");
GLES20.glBindAttribLocation(cam_mProgram, 1, "inputTextureCoordinate");
GLES20.glBindAttribLocation(cam_mProgram, 2, "s_texture");//new line
GLES20.glBindAttribLocation(cam_mProgram, 3, "a_normal");//new line
// Link the two shaders together into a program.
GLES20.glLinkProgram(cam_mProgram);
// Get the link status.
final int[] linkStatus = new int[1];
GLES20.glGetProgramiv(cam_mProgram, GLES20.GL_LINK_STATUS, linkStatus, 0);
// If the link failed, delete the program.
if (linkStatus[0] == 0)
{
GLES20.glDeleteProgram(cam_mProgram);
cam_mProgram = 0;
}
}

Android OpenGLES Brown square

So I'm trying to learn openGLES 2.0 and create a textured rectangle. Apparently I didn't follow all the instructions and now I've ended up with just a odd color square.
heres my shaders.
final String vertexShader =
"uniform mat4 u_MVPMatrix; \n" // A constant representing the combined model/view/projection matrix.
+ "attribute vec2 a_TexCoordinate;\n" // Per-vertex texture coordinate information we will pass in.
+ "attribute vec4 a_Position; \n" // Per-vertex position information we will pass in.
// + "attribute vec4 a_Color; \n" // Per-vertex color information we will pass in.
// + "varying vec4 v_Color; \n" // This will be passed into the fragment shader.
+ "varying vec2 v_TexCoordinate; \n" // This will be passed into the fragment shader.
+ "void main() \n" // The entry point for our vertex shader.
+ "{ \n"
+ " v_TexCoordinate = a_TexCoordinate;\n" // Pass the texture coordinate through to the fragment shader.
// It will be interpolated across the triangle.
+ " gl_Position = u_MVPMatrix \n" // gl_Position is a special variable used to store the final position.
+ " * a_Position; \n" // Multiply the vertex by the matrix to get the final point in
+ "} \n";
final String fragmentShader =
"precision mediump float; \n" // Set the default precision to medium. We don't need as high of a
// precision in the fragment shader.
+ "uniform sampler2D u_Texture; \n" // The input texture.
+ "uniform vec4 u_Color; \n" // This is the color from the vertex shader interpolated across the
// triangle per fragment.
+ "varying vec2 v_TexCoordinate; \n" // Interpolated texture coordinate per fragment.
+ "void main() \n" // The entry point for our fragment shader.
+ "{ \n"
+ " gl_FragColor = texture2D(u_Texture, v_TexCoordinate); \n"
+ "} \n";
Here is the load texture function
public static int loadTexture(final Context context, final int resourceId)
{
final int[] textureHandle = new int[1];
GLES20.glGenTextures(1, textureHandle, 0);
if (textureHandle[0] != 0)
{
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inScaled = false; // No pre-scaling
// Read in the resource
final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);
// Bind to the texture in OpenGL
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);
// Set filtering
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
// Load the bitmap into the bound texture.
GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
// Recycle the bitmap, since its data has been loaded into OpenGL.
bitmap.recycle();
}
if (textureHandle[0] == 0)
{
throw new RuntimeException("Error loading texture.");
}
return textureHandle[0];
}
And here is the drawFrame
#Override
public void onDrawFrame(GL10 gl) {
// Set the background clear color to gray.
GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
GLES20.glClearColor(0.5f, 0.5f, 0.5f, 0.5f);
mTextureUniformHandle = GLES20.glGetUniformLocation(programHandle, "u_Texture");
mTextureCoordinateHandle = GLES20.glGetAttribLocation(programHandle, "a_TexCoordinate");
// Set the active texture unit to texture unit 0.
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
// Bind the texture to this unit.
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mTextureDataHandle);
// Tell the texture uniform sampler to use this texture in the shader by binding to texture unit 0.
GLES20.glUniform1i(mTextureUniformHandle, 0);
// Draw the triangle facing straight on.
Matrix.setIdentityM(mModelMatrix, 0);
Matrix.translateM(mModelMatrix, 0, Fields.screen_width / 2, Fields.screen_height / 2, 0);
Matrix.scaleM(mModelMatrix, 0, Fields.screen_width / 4, Fields.screen_width / 4, 0);
drawTriangle(mTriangle1Vertices);
}
Any advice for getting rid of the wierd brown square and actually displaying the texture?
Edit: Here are the texture coordinates
public GL20Renderer(Context context) {
final float[] triangle1VerticesData = {
// X, Y, Z,
// R, G, B, A
-1f, 1f, 0.0f,
-1, -1, 0.0f,
1f, 1f, 0.0f,
-1f, -1f, 0.0f,
1f, -1f, 0.0f,
1f, 1f, 0.0f,
};
// Initialize the buffers.
mTriangle1Vertices = ByteBuffer.allocateDirect(triangle1VerticesData.length * mBytesPerFloat)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangle1Vertices.put(triangle1VerticesData).position(0);
final float[] triangle1TextureCoordinateData =
{
0.0f, 0.0f,
0.0f, 1.0f,
1.0f, 0.0f,
0.0f, 1.0f,
1.0f, 1.0f,
1.0f, 0.0f
};
mTriangleTextureCoordinates = ByteBuffer.allocateDirect(triangle1TextureCoordinateData.length * mBytesPerFloat)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
mTriangleTextureCoordinates.put(triangle1TextureCoordinateData).position(0);
this.context = context;
}
and here is the drawtriangle function
private void drawTriangle(final FloatBuffer aTriangleBuffer)
{
// Pass in the position information
aTriangleBuffer.position(mPositionOffset);
GLES20.glVertexAttribPointer(mPositionHandle, mPositionDataSize, GLES20.GL_FLOAT, false,
mStrideBytes, aTriangleBuffer);
GLES20.glEnableVertexAttribArray(mPositionHandle);
int colorHandle = GLES20.glGetUniformLocation(programHandle, "u_Color");
// Set color for drawing the triangle
GLES20.glUniform4f(colorHandle, 0.0f, 0.8f, 1.0f, 1.0f);
// This multiplies the view matrix by the model matrix, and stores the result in the MVP matrix
// (which currently contains model * view).
Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0);
// This multiplies the modelview matrix by the projection matrix, and stores the result in the MVP matrix
// (which now contains model * view * projection).
Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, 6);
}
Your drawTriangle code doesn't set the texture co-ordinates anywhere. Add some code something like this:
triangle1TextureCoordinateData.position(mPositionOffset * 2 / 3);
GLES20.glVertexAttribPointer(mTextureCoordinateHandle, 2, GLES20.GL_FLOAT, false,
0, triangle1TextureCoordinateData);
GLES20.glEnableVertexAttribArray(mTextureCoordinateHandle);
Note you can set the stride to zero if your data is packed in the buffer.

OpenGL ES 2.0 Scaling not working

I need to scale an object in OpenGL|ES 2.0. Shaders:
private final String vertexShaderCode =
"uniform mat4 uMVPMatrix;" +
"attribute vec4 vPosition;" +
"void main() {" +
//the matrix must be included as a modifier of gl_Position
" gl_Position = vPosition * uMVPMatrix;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
Projection:
Matrix.orthoM(mProjMatrix,0,
-1.0f, // Left
1.0f, // Right
-1.0f / ratio, // Bottom
1.0f / ratio, // Top
0.01f, // Near
10000.0f);
Drawing setup:
// Set the camera position (View matrix)
Matrix.setLookAtM(mVMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);
// Calculate the projection and view transformation
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mVMatrix, 0);
Actual render:
float[] scale = {5f,5f,1f};
Matrix.scaleM(scale_matrix, 0, scale[0], scale[1], scale[2]);
Matrix.multiplyMM(r_matrix, 0, scale_matrix, 0, mMVPMatrix, 0);
// Combine the rotation matrix with the projection and camera view
// Apply the projection and view transformation
GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, r_matrix, 0);
And it will not scale. I can see the triangle and I can rotate it. But scaling does not work.
Since vectors are column vectors in OpenGL you have to change the order of the matrix multiplication in your vertex shader:
gl_Position = uMVPMatrix*vPosition;

Transparency shader fills transparent fragments with clear color

I'm trying to make transparent object in OpenGL ES 2.0.
It's a live wallpaper, I'm using GLWallpaperService as a base class for this.
I'm setting up OpenGL in this way:
GLES20.glEnable(GLES20.GL_DEPTH_TEST);
GLES20.glDepthFunc(GLES20.GL_GEQUAL);
GLES20.glClearDepthf(0.0f);
GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
In Wallpaper initialization I set render mode:
setRenderMode(RENDERMODE_CONTINUOUSLY);
Shaders I use are taken from PowerVR sample OGLES2AlphaTest for alpha testing, which works fine on my HTC Desire device.
Here is the code for shaders:
private final String mVertexShader = "uniform highp mat4 uMVPMatrix;\n" +
"attribute highp vec4 aPosition;\n" +
"attribute highp vec2 aTextureCoord;\n" +
"varying mediump vec2 vTextureCoord;\n" +
"void main() {\n" +
" gl_Position = uMVPMatrix * aPosition;\n" +
" vTextureCoord = aTextureCoord;\n" +
"}\n";
private final String mFragmentShader = "precision mediump float;\n" +
"varying mediump vec2 vTextureCoord;\n" +
"uniform sampler2D sTexture;\n" +
"void main() {\n" +
" vec4 base = texture2D(sTexture, vTextureCoord);\n" +
" if(base.a < 0.5){ discard; }\n" +
" gl_FragColor = base;\n" +
"}\n";
Code for rendering frame:
public void onDrawFrame(GL10 glUnused) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
GLES20.glUseProgram(mProgram);
checkGlError("glUseProgram");
GLES20.glDisable(GLES20.GL_BLEND);
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");
long time = SystemClock.uptimeMillis() % 4000L;
float angle = 0.090f * ((int) time);
time = SystemClock.uptimeMillis();// % 4000L;
angle = 0.030f * ((int) time);
Matrix.setRotateM(mMMatrix, 0, angle, 0, 1.0f, 0);
Matrix.scaleM(mMMatrix, 0, 0.075f, 0.075f, 0.075f);
Matrix.multiplyMM(mMVPMatrix, 0, mVMatrix, 0, mMMatrix, 0);
Matrix.multiplyMM(mMVPMatrix, 0, mProjMatrix, 0, mMVPMatrix, 0);
GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0);
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, numPolys);
checkGlError("glDrawArrays");
}
Resulting image of rendering: http://imgur.com/hNqm0.
But if I use
setRenderMode(RENDERMODE_WHEN_DIRTY);
for initializing wallpaper, I can get correct rendering, but only 1 still frame after I switch to some other activity and back to wallpaper. If I try to call requestRender() periodically I still get wrong transparency.
OK, I resolved it. It was caused by writing to depth buffer.

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