多重采样MSAA

GLSurfaceView设置多重采样

/*** 抗锯齿EGLConfigChooser** author weiss* email kleinminamo@gmail.com* created 2018/7/3.*/
public class MSAAConfigChooser implements GLSurfaceView.EGLConfigChooser {@Overridepublic EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {int attribs[] = {EGL10.EGL_LEVEL, 0,EGL10.EGL_RENDERABLE_TYPE, 4,  // EGL_OPENGL_ES2_BITEGL10.EGL_COLOR_BUFFER_TYPE, EGL10.EGL_RGB_BUFFER,EGL10.EGL_RED_SIZE, 8,EGL10.EGL_GREEN_SIZE, 8,EGL10.EGL_BLUE_SIZE, 8,EGL10.EGL_DEPTH_SIZE, 24,EGL10.EGL_SAMPLE_BUFFERS, 1,EGL10.EGL_SAMPLES, 4,  // 在这里修改MSAA的倍数，4就是4xMSAA，再往上开程序可能会崩EGL10.EGL_NONE};EGLConfig[] configs = new EGLConfig[1];int[] configCounts = new int[1];egl.eglChooseConfig(display, attribs, configs, 1, configCounts);if (configCounts[0] == 0) {// Failed! Error handling.return null;} else {return configs[0];}}
}
复制代码

开启MULTISAMPLE

GLES20.glEnable(GL10.GL_MULTISAMPLE);
复制代码

后处理FXAA Shader

#ifndef FXAA_REDUCE_MIN#define FXAA_REDUCE_MIN   (1.0/ 128.0)
#endif
#ifndef FXAA_REDUCE_MUL#define FXAA_REDUCE_MUL   (1.0 / 8.0)
#endif
#ifndef FXAA_SPAN_MAX#define FXAA_SPAN_MAX     8.0
#endif//optimized version for mobile, where dependent
//texture reads can be a bottleneck
vec4 fxaa(sampler2D tex, vec2 fragCoord, vec2 resolution,vec2 v_rgbNW, vec2 v_rgbNE,vec2 v_rgbSW, vec2 v_rgbSE,vec2 v_rgbM) {vec4 color;mediump vec2 inverseVP = vec2(1.0 / resolution.x, 1.0 / resolution.y);vec3 rgbNW = texture2D(tex, v_rgbNW).xyz;vec3 rgbNE = texture2D(tex, v_rgbNE).xyz;vec3 rgbSW = texture2D(tex, v_rgbSW).xyz;vec3 rgbSE = texture2D(tex, v_rgbSE).xyz;vec4 texColor = texture2D(tex, v_rgbM);vec3 rgbM  = texColor.xyz;vec3 luma = vec3(0.299, 0.587, 0.114);float lumaNW = dot(rgbNW, luma);float lumaNE = dot(rgbNE, luma);float lumaSW = dot(rgbSW, luma);float lumaSE = dot(rgbSE, luma);float lumaM  = dot(rgbM,  luma);float lumaMin = min(lumaM, min(min(lumaNW, lumaNE), min(lumaSW, lumaSE)));float lumaMax = max(lumaM, max(max(lumaNW, lumaNE), max(lumaSW, lumaSE)));mediump vec2 dir;dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));dir.y =  ((lumaNW + lumaSW) - (lumaNE + lumaSE));float dirReduce = max((lumaNW + lumaNE + lumaSW + lumaSE) *(0.25 * FXAA_REDUCE_MUL), FXAA_REDUCE_MIN);float rcpDirMin = 1.0 / (min(abs(dir.x), abs(dir.y)) + dirReduce);dir = min(vec2(FXAA_SPAN_MAX, FXAA_SPAN_MAX),max(vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),dir * rcpDirMin)) * inverseVP;vec3 rgbA = 0.5 * (texture2D(tex, fragCoord * inverseVP + dir * (1.0 / 3.0 - 0.5)).xyz +texture2D(tex, fragCoord * inverseVP + dir * (2.0 / 3.0 - 0.5)).xyz);vec3 rgbB = rgbA * 0.5 + 0.25 * (texture2D(tex, fragCoord * inverseVP + dir * -0.5).xyz +texture2D(tex, fragCoord * inverseVP + dir * 0.5).xyz);float lumaB = dot(rgbB, luma);if ((lumaB < lumaMin) || (lumaB > lumaMax))color = vec4(rgbA, texColor.a);elsecolor = vec4(rgbB, texColor.a);return color;
}
复制代码

特别注意用了后处理FBO，多重采样会失效，离屏渲染需要对FBO进行多重采样

FBO

    const char* __glExtensions = (const char*)glGetString(GL_EXTENSIONS);if(strstr(__glExtensions, "GL_IMG_multisampled_render_to_texture")){if(glFramebufferTexture2DMultisampleIMG_ == NULL){glFramebufferTexture2DMultisampleIMG_ = (PFNGLFRAMEBUFFERTEXTURE2DMULTISAMPLEIMGPROC )eglGetProcAddress ( "glFramebufferTexture2DMultisampleIMG" );}}else if(strstr(__glExtensions, "GL_EXT_multisampled_render_to_texture")){if(glFramebufferTexture2DMultisampleIMG_ == NULL){glFramebufferTexture2DMultisampleIMG_ = (PFNGLFRAMEBUFFERTEXTURE2DMULTISAMPLEIMGPROC )eglGetProcAddress ( "glFramebufferTexture2DMultisampleEXT" );}}//glFramebufferTexture2DMultisampleIMG_if(_multiSample){GL_ASSERT( glFramebufferTexture2DMultisampleIMG_(GL_FRAMEBUFFER, attachment, textureTarget, _renderTargets[index]->getTexture()->getHandle(), 0, 4););} else{GL_ASSERT( glFramebufferTexture2D(GL_FRAMEBUFFER, attachment, textureTarget, _renderTargets[index]->getTexture()->getHandle(), 0));}
复制代码

RBO

    const char* __glExtensions = (const char*)glGetString(GL_EXTENSIONS);if(strstr(__glExtensions, "GL_IMG_multisampled_render_to_texture")){if(glRenderbufferStorageMultisampleIMG_ == NULL){glRenderbufferStorageMultisampleIMG_ = (PFNGLRENDERBUFFERSTORAGEMULTISAMPLEIMGPROC )eglGetProcAddress ( "glRenderbufferStorageMultisampleIMG" );}}else if(strstr(__glExtensions, "GL_EXT_multisampled_render_to_texture")){if(glRenderbufferStorageMultisampleIMG_ == NULL){glRenderbufferStorageMultisampleIMG_ = (PFNGLRENDERBUFFERSTORAGEMULTISAMPLEIMGPROC )eglGetProcAddress ( "glRenderbufferStorageMultisampleEXT" );}}//glRenderbufferStorageMultisampleIMG_glRenderbufferStorageMultisampleIMG_(GL_RENDERBUFFER, 4,GL_DEPTH24_STENCIL8, width, height); // w width, h height.
复制代码