Android OpenGL ES抗锯齿

小灰灰 2022-01-19 00:43 248阅读 0赞

## 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 {
        @Override
        public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
    
            int attribs[] = {
                    EGL10.EGL_LEVEL, 0,
                    EGL10.EGL_RENDERABLE_TYPE, 4,  // EGL_OPENGL_ES2_BIT
                    EGL10.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);
        else
            color = 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

转载于:https://juejin.im/post/5c89f7b8e51d453b5a68ffee