Android Java 版本的 MSAA OpenGL ES 多重采样

最近多次被小伙伴问到 OpenGL 多重采样，其实前面文章里多次讲过了，就是构建2个缓冲区，多重采样缓冲区和目标解析缓冲区。

代码流程

// Framebuffer IDs
private int msaaFBO;
private int msaaColorBuffer;
private int msaaDepthBuffer;private int resolveFBO;
private int resolveTexture;public void initFramebuffers(int width, int height) {// Step 1: Create MSAA FBOint[] fbo = new int[1];GLES30.glGenFramebuffers(1, fbo, 0);msaaFBO = fbo[0];GLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, msaaFBO);// Create MSAA color bufferint[] renderbuffer = new int[1];GLES30.glGenRenderbuffers(1, renderbuffer, 0);msaaColorBuffer = renderbuffer[0];GLES30.glBindRenderbuffer(GLES30.GL_RENDERBUFFER, msaaColorBuffer);GLES30.glRenderbufferStorageMultisample(GLES30.GL_RENDERBUFFER, 4, GLES30.GL_RGBA8, width, height); // 4x MSAAGLES30.glFramebufferRenderbuffer(GLES30.GL_FRAMEBUFFER, GLES30.GL_COLOR_ATTACHMENT0, GLES30.GL_RENDERBUFFER, msaaColorBuffer);// Create MSAA depth bufferGLES30.glGenRenderbuffers(1, renderbuffer, 0);msaaDepthBuffer = renderbuffer[0];GLES30.glBindRenderbuffer(GLES30.GL_RENDERBUFFER, msaaDepthBuffer);GLES30.glRenderbufferStorageMultisample(GLES30.GL_RENDERBUFFER, 4, GLES30.GL_DEPTH_COMPONENT16, width, height);GLES30.glFramebufferRenderbuffer(GLES30.GL_FRAMEBUFFER, GLES30.GL_DEPTH_ATTACHMENT, GLES30.GL_RENDERBUFFER, msaaDepthBuffer);if (GLES30.glCheckFramebufferStatus(GLES30.GL_FRAMEBUFFER) != GLES30.GL_FRAMEBUFFER_COMPLETE) {throw new RuntimeException("MSAA Framebuffer is not complete!");}// Step 2: Create Resolve FBOGLES30.glGenFramebuffers(1, fbo, 0);resolveFBO = fbo[0];GLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, resolveFBO);// Create texture for resolved resultint[] texture = new int[1];GLES30.glGenTextures(1, texture, 0);resolveTexture = texture[0];GLES30.glBindTexture(GLES30.GL_TEXTURE_2D, resolveTexture);GLES30.glTexImage2D(GLES30.GL_TEXTURE_2D, 0, GLES30.GL_RGBA, width, height, 0, GLES30.GL_RGBA, GLES30.GL_UNSIGNED_BYTE, null);GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MIN_FILTER, GLES30.GL_LINEAR);GLES30.glTexParameteri(GLES30.GL_TEXTURE_2D, GLES30.GL_TEXTURE_MAG_FILTER, GLES30.GL_LINEAR);GLES30.glFramebufferTexture2D(GLES30.GL_FRAMEBUFFER, GLES30.GL_COLOR_ATTACHMENT0, GLES30.GL_TEXTURE_2D, resolveTexture, 0);if (GLES30.glCheckFramebufferStatus(GLES30.GL_FRAMEBUFFER) != GLES30.GL_FRAMEBUFFER_COMPLETE) {throw new RuntimeException("Resolve Framebuffer is not complete!");}// Unbind framebufferGLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, 0);
}public void renderScene() {// Step 3: Render to MSAA FBOGLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, msaaFBO);GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT);// Render your scene here...// Step 4: Resolve to textureGLES30.glBindFramebuffer(GLES30.GL_READ_FRAMEBUFFER, msaaFBO);GLES30.glBindFramebuffer(GLES30.GL_DRAW_FRAMEBUFFER, resolveFBO);GLES30.glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, GLES30.GL_COLOR_BUFFER_BIT, GLES30.GL_NEAREST);// Step 5: Unbind framebuffersGLES30.glBindFramebuffer(GLES30.GL_FRAMEBUFFER, 0);// Step 6: Use resolveTexture for further processing (e.g., render to screen)renderQuadWithTexture(resolveTexture);
}