android - 优化 Android/iOS 设备上的巨大 VBO 绘图-6ren

android - 优化 Android/iOS 设备上的巨大 VBO 绘图

转载作者：塔克拉玛干更新时间：2023-11-02 23:25:42

我需要做的是在移动设备(OpenGL ES2.0，Android 4.2)上渲染一个比较大的等距 map 。我为地形使用 1 个 VBO，为阴影层使用 1 个 VBO，为对象层使用 1 个 VBO。性能是问题所在，即使是第一个 VBO。

我们开始吧，我有用于填充 VBO 的数据类型:

typedef struct _ovlndVertex
{
    GLshort x;
    GLshort y;
} ovlndVertex;

typedef struct _ovlndTexture {
    GLfloat u;
    GLfloat v;
} ovlndTexture;


typedef struct _TexturedVertex
{
    ovlndVertex        vertices;
    ovlndTexture       texCoords;
    GLshort textureId;
} TexturedVertex;

假设我们正在渲染一个 256x256 大小的 map ，每个图 block 有 4 个顶点，这使我们在 VBO 中有 256x256x4 = 262144 个顶点。鉴于 sizeof(TexturedVertex) == 16，这是 4194304 字节的原始 VBO 数据(大约 4MB)。

主要的渲染工作是在着色器中完成的。这是他们的代码:

顶点着色器:

attribute vec4 a_position;                            
attribute vec2 a_texCoord;                            
//attribute vec4 a_color;
attribute vec2 a_textureId;                              

uniform        mat4 u_MVPMatrix;                        

#ifdef GL_ES                                        
//varying lowp vec4 v_fragmentColor;                    
varying lowp vec2 v_texCoord;
#else                                                
//varying vec4 v_fragmentColor;                        
varying vec2 v_texCoord;
#endif                                                

varying float v_textureId;

void main()                                            
{                                                    
    gl_Position = u_MVPMatrix * a_position;            
//  v_fragmentColor = a_color;
    v_texCoord = a_texCoord;                        
    v_textureId = a_textureId.x;
}

fragment 着色器:

#ifdef GL_ES                                
precision lowp float;
precision lowp int;
precision lowp sampler2D;
#endif                                        

//varying vec4 v_fragmentColor;                
varying vec2 v_texCoord;
//uniform sampler2D u_texture0, u_texture1, u_texture2;
uniform sampler2D u_textures[16];
varying float v_textureId;
uniform int u_idxOffset;

void main()                                    
{                                  
    // strange enough, but binary search below works WAY faster than
    // plain texture array referencing by index like:
//    int idx = int(v_textureId) - u_idxOffset;
//    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[idx], v_texCoord);

    int index = int(v_textureId) - u_idxOffset;
    if(index < 8) //0-7
    {
        if(index < 4) // 0-4
        {
            if(index < 2) //0-1
            {
                if(index < 1)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[0], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[1], v_texCoord);
                }
            } else // 2-3
            {
                if(index < 3)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[2], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[3], v_texCoord);
                }
            }
        } else //4-7
        {
            if(index < 6) //4-5
            {
                if(index < 5)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[4], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[5], v_texCoord);
                }
            } else // 6-7
            {
                if(index < 7)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[6], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[7], v_texCoord);
                }
            }
        }
    } else //8-15
    {
        if(index < 12) //8-11
        {
            if(index < 10) //8-9
            {
                if(index < 9)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[8], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[9], v_texCoord);
                }
            } else // 10-11
            {
                if(index < 11)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[10], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[11], v_texCoord);
                }
            }
        } else //12-15
        {
            if(index < 14) //12-13
            {
                if(index < 13)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[12], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[13], v_texCoord);
                }
            } else // 14-15
            {
                if(index < 15)
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[14], v_texCoord);
                }
                else
                {
                    gl_FragColor = /*v_fragmentColor * */texture2D(u_textures[15], v_texCoord);
                }
            }
        }
    }
}

是的，我知道 OpenGL ES 会剔除视口(viewport)外的顶点，而且效果很好。在高缩放级别上，它在设备上平滑地呈现 60FPS，但是，如果我缩小以查看所有 map (这是主要点)，即使没有对象渲染，FPS 也会下降到 20-30，有对象时下降到 4-5渲染(另外 2 个类似的 VBO)。

这是典型的慢速渲染帧的 ADT 的 OpenGL ES Tracer 输出:(挂钟时间:0.49ms，线程时间0.37ms)

glClear(mask = 16640)
glUseProgram(program = 22)
glBindTexture(target = GL_TEXTURE_2D, texture = 2)
glActiveTexture(texture = GL_TEXTURE1)
glActiveTexture(texture = GL_TEXTURE2)
glActiveTexture(texture = GL_TEXTURE3)
glActiveTexture(texture = GL_TEXTURE4)
glActiveTexture(texture = GL_TEXTURE5)
glActiveTexture(texture = GL_TEXTURE6)
glActiveTexture(texture = GL_TEXTURE7)
glActiveTexture(texture = GL_TEXTURE8)
glActiveTexture(texture = GL_TEXTURE9)
glActiveTexture(texture = GL_TEXTURE10)
glActiveTexture(texture = GL_TEXTURE11)
glActiveTexture(texture = GL_TEXTURE12)
glUniform1i(location = 1, x = 0)
glBindBuffer(target = GL_ARRAY_BUFFER, buffer = 123)
glVertexAttribPointer(indx = 0, size = 2, type = GL_SHORT, normalized = false, stride = 16, ptr = 0x0)
glEnableVertexAttribArray(index = 1)
glEnableVertexAttribArray(index = 2)
glEnableVertexAttribArray(index = 0)
glEnableVertexAttribArray(index = 3)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 16, ptr = 0x0)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 16, ptr = 0x4)
glVertexAttribPointer(indx = 3, size = 1, type = GL_SHORT, normalized = false, stride = 16, ptr = 0xc)
glBindBuffer(target = GL_ELEMENT_ARRAY_BUFFER, buffer = 124)
glDrawElements(mode = GL_TRIANGLES, count = 469374, type = GL_UNSIGNED_INT, indices = 0x0)
glBindBuffer(target = GL_ARRAY_BUFFER, buffer = 0)
glBindBuffer(target = GL_ELEMENT_ARRAY_BUFFER, buffer = 0)
glActiveTexture(texture = GL_TEXTURE0)
glUseProgram(program = 7)
glDisableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x775470c0)
glVertexAttribPointer(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x775470e0)
glVertexAttribPointerData(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 8, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 16, ptr = 0x??, minIndex = 0, maxIndex = 4)
glBlendFunc(sfactor = GL_SRC_ALPHA, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUseProgram(program = 1)
glBlendFunc(sfactor = GL_LINES, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glBindTexture(target = GL_TEXTURE_2D, texture = 0)
glEnableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77530800)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77530810)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x7753080c)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x775295f8)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529608)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77529604)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529878)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529888)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77529884)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
eglSwapBuffers

仅供引用，这是典型的快速渲染 GUI 框架(实际上是主菜单，它给了我 60FPS):(挂钟时间:1.10MS，线程时间0.70MS)

glClear(mask = 16640)
glUseProgram(program = 7)
glDisableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x77538880)
glVertexAttribPointer(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x775388a0)
glBlendFunc(sfactor = GL_SRC_ALPHA, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glVertexAttribPointerData(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 8, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 16, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUseProgram(program = 1)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, 0.093229175, -0.17300725, 0.0, 1.0])
glBlendFunc(sfactor = GL_LINES, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glBindTexture(target = GL_TEXTURE_2D, texture = 1)
glEnableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77546f08)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77546f18)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77546f14)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.23489577, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538cb0)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538cc0)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77538cbc)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.20677078, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538f00)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538f10)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77538f0c)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.15572912, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77539150)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77539160)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x7753915c)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.1057291, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x775393a0)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x775393b0)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x775393ac)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.0567708, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77537bc0)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77537bd0)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77537bcc)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -0.020312428, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77537e10)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77537e20)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77537e1c)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, 0.02239585, -0.17300725, 0.0, 1.0])
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538060)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77538070)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x7753806c)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUseProgram(program = 7)
glDisableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x77533090)
glVertexAttribPointerData(indx = 0, size = 2, type = GL_FLOAT, normalized = false, stride = 8, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 16, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_FLOAT, normalized = false, stride = 0, ptr = 0x775330b0)
glBlendFunc(sfactor = GL_SRC_ALPHA, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glUseProgram(program = 1)
glUniformMatrix4fv(location = 0, count = 1, transpose = false, value = [0.0010416667, 0.0, 0.0, 0.0, 0.0, 0.0018115942, 0.0, 0.0, 0.0, 0.0, -9.765625E-4, 0.0, -1.0, -1.0, 0.0, 1.0])
glBlendFunc(sfactor = GL_LINES, dfactor = GL_ONE_MINUS_SRC_ALPHA)
glBindTexture(target = GL_TEXTURE_2D, texture = 0)
glEnableVertexAttribArray(index = 2)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77530800)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77530810)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x7753080c)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x775295f8)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529608)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77529604)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
glVertexAttribPointer(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529878)
glVertexAttribPointer(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x77529888)
glVertexAttribPointer(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x77529884)
glVertexAttribPointerData(indx = 0, size = 3, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 1, size = 4, type = GL_UNSIGNED_BYTE, normalized = true, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glVertexAttribPointerData(indx = 2, size = 2, type = GL_FLOAT, normalized = false, stride = 24, ptr = 0x??, minIndex = 0, maxIndex = 4)
glDrawArrays(mode = GL_TRIANGLE_STRIP, first = 0, count = 4)
eglSwapBuffers

这使 OpenGL Tracers 对我来说毫无用处，因为较慢的渲染帧显示的时间(包括挂钟和线程)更多。这是否意味着问题隐藏在着色器的某处？我如何介绍他们？

到目前为止我尝试了什么:

将所有 GLuint 更改为 GLshort 以最小化缓冲区大小(给我 28 到 16 字节的顶点结构 sizeof 优化)
尝试使用 GL_DYNAMIC_DRAW/GL_STATIC_DRAW 方法将数据发送到 VBO(对我来说没有区别)
尽我所能尝试使用 lowp
尝试了单纹理渲染(没有区别，这让我觉得着色器做得很好)
将 OpenGL 调用减少到绝对最小值(您可以在上面查看 OGL 调用日志)
删除了所有可能破坏管线渲染的 glGet* 函数

我有什么可以优化的建议吗？

最佳答案

你已经做得很好了。可能没有更多的空间来进行更多的微优化。

因为 drawcall 的数量非常少，所以使用 VAO/VertexArrays 从渲染循环中移除 glVertexAttribPointer 应该不会有太大帮助。

4 vertices per tile

为什么要使用 GL_TRIANGLE_STRIP 和 glDrawArrays ？带有索引的 glDrawElements 会给你更多的灵 active (见后...)。

20-30 even without object rendering and to 4-5 with object rendering (2 additional similar VBOs).

好的。所以你最终得到大约 800k 个顶点。正确的？去年我遇到过类似的问题(1000k 个顶点)。我最终选择发送更多绘图调用而不是使用复杂的着色器。是的，绑定(bind)大量数据(绑定(bind) 16 个纹理!)会降低此类设备上的一切速度。

if I zoom out to view all the map (this is the primary point) the FPS drops

在 iPad 2 上，屏幕上的 1000k 个顶点(每个顶点的数据比你多得多)应该渲染得更快:超过 20 fps。

看来您的大部分数据都是静态的。 您可以尝试为每个纹理构建一个 vbo 或一个索引列表(我不知道哪个更快)，大大简化您的 fragment 着色器。

用所有“静态数据”(顶点位置、纹理坐标)绑定(bind)一个 vbo
对于每个纹理
1. 绑定(bind)纹理
2. 将 glDrawElements 与“特定于纹理”的索引列表一起使用。

您可以将索引存储在缓冲区中:glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ...)或者，如果索引是动态的，您可以将索引直接传递给 glBindBuffer。它可能比您想象的要快。

最后一个细节:到处都是低电平是危险的。试试 mediump。

祝你好运，你正在触及设备限制!

关于android - 优化 Android/iOS 设备上的巨大 VBO 绘图，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25097085/

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android - 优化 Android/iOS 设备上的巨大 VBO 绘图