As I understand it, from GLES30 there is no more gl_FragColor buffer (I saw it HERE )
Since I cannot read "Special Variables", how can I read the "output" buffer?
This is my code:
private static final String FRAGMENT_SHADER = "#version 300 es\n"+ "#extension GL_OES_EGL_image_external_essl3 : require\n" + "precision mediump float;\n" + // highp here doesn't seem to matter "in vec2 vTextureCoord;\n" + "uniform sampler2D sTexture;\n" + "out vec4 fragColor ;\n" + "void main() {\n" + " vec4 tc = texture(sTexture, vTextureCoord);\n" + " fragColor.r = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + " fragColor.g = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + " fragColor.b = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + "}\n";
Here I tried to read the data:
ByteBuffer mPixelBuf = ByteBuffer.allocateDirect(mWidth * mHeight * 4); mPixelBuf.order(ByteOrder.LITTLE_ENDIAN); GLES30.glReadPixels(startX, startY, frameWidth, frameHeight, GLES30.GL_RGBA, GLES30.GL_UNSIGNED_BYTE, mPixelBuf);
There are no gl errors in the code.
The output of mPixelBuf only zeros.
How can I make sure fragColor reading?
thanks
Update1- Full texture rendering code:
package com.MES.YOtm.AnalyzingAdapter; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import android.graphics.SurfaceTexture; import android.opengl.GLES11Ext; import android.opengl.GLES30; import android.opengl.Matrix; import android.util.Log; /** * Code for rendering a texture onto a surface using OpenGL ES 2.0. */ public class STextureRender { private static final String TAG = "Myopengl"; private int zoom; 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 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, }; private FloatBuffer mTriangleVertices; private static final String VERTEX_SHADER = "#version 300 es\n"+ "uniform mat4 uMVPMatrix;\n" + "uniform mat4 uSTMatrix;\n" + "in vec4 aPosition;\n" + "in vec4 aTextureCoord;\n" + "out vec2 vTextureCoord;\n" + "void main() {\n" + " gl_Position = uMVPMatrix * aPosition;\n" + " vTextureCoord = (uSTMatrix * aTextureCoord).xy;\n" + "}\n"; //Smapler2D private static final String FRAGMENT_SHADER = "#version 300 es\n"+ "#extension GL_OES_EGL_image_external_essl3 : require\n" + "precision mediump float;\n" + // highp here doesn't seem to matter "in vec2 vTextureCoord;\n" + "uniform mediump sampler2D sTexture;\n" + "layout(location = 0) out mediump vec4 fragColor ;\n" + "void main() {\n" + " vec4 tc = texture(sTexture, vTextureCoord);\n" + " fragColor.r = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + " fragColor.g = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + " fragColor.b = tc.r * 0.3 + tc.g * 0.59 + tc.b * 0.11;\n" + "}\n"; private float[] mMVPMatrix = new float[16]; private float[] mSTMatrix = new float[16]; private int mProgram; private int mTextureID = -12345; private int muMVPMatrixHandle; private int muSTMatrixHandle; private int maPositionHandle; private int maTextureHandle; public STextureRender(int _zoom) { Log.v("My Error", "Start STextureRender constructor"); try { mTriangleVertices = ByteBuffer.allocateDirect( mTriangleVerticesData.length * FLOAT_SIZE_BYTES) .order(ByteOrder.nativeOrder()).asFloatBuffer(); mTriangleVertices.put(mTriangleVerticesData).position(0); Matrix.setIdentityM(mSTMatrix, 0); zoom = _zoom; } catch(Exception ex) { Log.v("My Error", "STextureRender Error = " + ex.toString()); } Log.v("My Error", "End STextureRender constructor"); } public int getTextureId() { return mTextureID; } /** * Draws the external texture in SurfaceTexture onto the current EGL surface. */ public void drawFrame(SurfaceTexture st, boolean invert) { checkGlError("onDrawFrame start"); try { st.getTransformMatrix(mSTMatrix); if (invert) { mSTMatrix[5] = -mSTMatrix[5]; mSTMatrix[13] = 1.0f - mSTMatrix[13]; } GLES30.glClearColor(0.0f, 1.0f, 0.0f, 1.0f); GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT); GLES30.glUseProgram(mProgram); checkGlError("glUseProgram"); GLES30.glActiveTexture(GLES30.GL_TEXTURE0); GLES30.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID); mTriangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET); GLES30.glVertexAttribPointer(maPositionHandle, 3, GLES30.GL_FLOAT, false, TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices); checkGlError("glVertexAttribPointer maPosition"); GLES30.glEnableVertexAttribArray(maPositionHandle); checkGlError("glEnableVertexAttribArray maPositionHandle"); mTriangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET); GLES30.glVertexAttribPointer(maTextureHandle, 2, GLES30.GL_FLOAT, false, TRIANGLE_VERTICES_DATA_STRIDE_BYTES, mTriangleVertices); checkGlError("glVertexAttribPointer maTextureHandle"); GLES30.glEnableVertexAttribArray(maTextureHandle); checkGlError("glEnableVertexAttribArray maTextureHandle"); Matrix.setIdentityM(mMVPMatrix, 0); GLES30.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, mMVPMatrix, 0); GLES30.glUniformMatrix4fv(muSTMatrixHandle, 1, false, mSTMatrix, 0); GLES30.glDrawArrays(GLES30.GL_TRIANGLE_STRIP, 0, 4); checkGlError("glDrawArrays"); } catch(Exception ex) { Log.v("My Error", "drawFrame Error = " + ex.toString()); } } /** * Initializes GL state. Call this after the EGL surface has been created and made current. */ public void surfaceCreated() { try { mProgram = createProgram(VERTEX_SHADER, FRAGMENT_SHADER); if (mProgram == 0) { throw new RuntimeException("failed creating program"); } maPositionHandle = GLES30.glGetAttribLocation(mProgram, "aPosition"); checkGlError("glGetAttribLocation aPosition"); if (maPositionHandle == -1) { throw new RuntimeException("Could not get attrib location for aPosition"); } maTextureHandle = GLES30.glGetAttribLocation(mProgram, "aTextureCoord"); checkGlError("glGetAttribLocation aTextureCoord"); if (maTextureHandle == -1) { throw new RuntimeException("Could not get attrib location for aTextureCoord"); } muMVPMatrixHandle = GLES30.glGetUniformLocation(mProgram, "uMVPMatrix"); checkGlError("glGetUniformLocation uMVPMatrix"); if (muMVPMatrixHandle == -1) { throw new RuntimeException("Could not get attrib location for uMVPMatrix"); } muSTMatrixHandle = GLES30.glGetUniformLocation(mProgram, "uSTMatrix"); checkGlError("glGetUniformLocation uSTMatrix"); if (muSTMatrixHandle == -1) { throw new RuntimeException("Could not get attrib location for uSTMatrix"); } int[] textures = new int[1]; GLES30.glGenTextures(1, textures, 0); mTextureID = textures[0]; GLES30.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, mTextureID); checkGlError("glBindTexture mTextureID"); GLES30.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES30.GL_TEXTURE_MIN_FILTER, GLES30.GL_NEAREST); GLES30.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES30.GL_TEXTURE_MAG_FILTER, GLES30.GL_LINEAR); GLES30.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES30.GL_TEXTURE_WRAP_S, GLES30.GL_CLAMP_TO_EDGE); GLES30.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES30.GL_TEXTURE_WRAP_T, GLES30.GL_CLAMP_TO_EDGE); checkGlError("glTexParameter"); } catch(Exception ex) { Log.v("My Error", "surfaceCreated Error = " + ex.toString()); } } /** * Replaces the fragment shader. Pass in null to reset to default. */ public void changementShader(String fragmentShader) { try { if (fragmentShader == null) { fragmentShader = FRAGMENT_SHADER; } GLES30.glDeleteProgram(mProgram); mProgram = createProgram(VERTEX_SHADER, fragmentShader); if (mProgram == 0) { Log.v("My Error", "failed creating program"); throw new RuntimeException("failed creating program"); } } catch(Exception ex) { Log.v("My Error", " changementShader Error = " + ex.toString()); } } private int loadShader(int shaderType, String source) { try { int shader = GLES30.glCreateShader(shaderType); checkGlError("glCreateShader type=" + shaderType); GLES30.glShaderSource(shader, source); GLES30.glCompileShader(shader); int[] compiled = new int[1]; GLES30.glGetShaderiv(shader, GLES30.GL_COMPILE_STATUS, compiled, 0); if (compiled[0] == 0) { Log.e(TAG, "Could not compile shader " + shaderType + ":"); Log.e(TAG, " " + GLES30.glGetShaderInfoLog(shader)); GLES30.glDeleteShader(shader); shader = 0; } return shader; } catch(Exception ex) { Log.v("My Error", "loadShader Error = " + ex.toString()); return 0; } } private int createProgram(String vertexSource, String fragmentSource) { try { int vertexShader = loadShader(GLES30.GL_VERTEX_SHADER, vertexSource); if (vertexShader == 0) { return 0; } int pixelShader = loadShader(GLES30.GL_FRAGMENT_SHADER, fragmentSource); if (pixelShader == 0) { return 0; } int program = GLES30.glCreateProgram(); checkGlError("glCreateProgram"); if (program == 0) { Log.e(TAG, "Could not create program"); } GLES30.glAttachShader(program, vertexShader); checkGlError("glAttachShader"); GLES30.glAttachShader(program, pixelShader); checkGlError("glAttachShader"); GLES30.glLinkProgram(program); int[] linkStatus = new int[1]; GLES30.glGetProgramiv(program, GLES30.GL_LINK_STATUS, linkStatus, 0); if (linkStatus[0] != GLES30.GL_TRUE) { Log.e(TAG, "Could not link program: "); Log.e(TAG, GLES30.glGetProgramInfoLog(program)); GLES30.glDeleteProgram(program); program = 0; } return program; } catch(Exception ex) { Log.v("My Error", "createProgram Error = " + ex.toString()); return 0; } } public void checkGlError(String op) { int error; while ((error = GLES30.glGetError()) != GLES30.GL_NO_ERROR) { Log.e(TAG, op + ": glError " + error); throw new RuntimeException(op + ": glError " + error); } } }