我需要做的是在移动设备(OpenGL ES2.0,Android 4.2)上渲染一个相对较大的等轴测图。我将1 VBO用于地形,将1 VBO用于阴影层并将1 VBO用于对象层。
即使使用第一个VBO,性能也是问题所在。

到这里,我具有用于填充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;

假设我们要渲染一个256x256尺寸的贴图,每个图块4个顶点,这在VBO中为我们提供了256x256x4 = 262144个顶点。给定sizeof(TexturedVertex)== 16,这是4194304字节的原始VBO数据(大约4MB)。

主要渲染工作在着色器中完成。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,我知道视口(viewport)外部顶点的OpenGL ES剔除,并且效果很好。在高缩放级别下,它可以在设备上平滑显示60FPS,但是,如果我缩小以查看所有 map (这是主要点),则即使没有对象渲染,FPS也会下降到20-30,而有对象则下降到4-5渲染(另外2个类似的VBO)。

这是ADT的OpenGL ES Tracer输出,用于典型的慢速渲染帧:
(壁钟时间: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,主菜单为我提供了60FPS):
(壁钟时间: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,因为渲染速度更快的帧显示的时间(壁钟和线程)都比慢的帧多。这是否意味着问题隐藏在着色器中的某处?如何配置他们?

到目前为止我尝试过的是:
  • 将所有GLuint更改为GLshort以最小化缓冲区大小(使我对顶点结构sizeof的优化为28到16字节)
  • 使用GL_DYNAMIC_DRAW/GL_STATIC_DRAW方法发送数据到VBO(对我来说没有区别)
  • 尝试在任何我可以使用的地方使用lowp
  • 尝试了单纹理渲染(没有区别,这使我认为着色器效果很好)
  • 将OpenGL调用减少到绝对最小值(您可以在上面看到OGL调用日志)
  • 删除了所有可能破坏渲染
  • 的管道的glGet *函数

    有什么建议我可以优化吗?

    最佳答案

    你已经做好了可能没有更多的空间进行更多的微优化。

    因为只有很少的调用,所以使用VAO/VertexArrays从渲染循环中删除glVertexAttribPointer应该不会有太大帮助。



    为什么要使用GL_TRIANGLE_STRIP和glDrawArrays?带有索引的glDrawElements将为您提供更大的灵活性(请参阅下文...)。



    好的。这样最终得到约80万个顶点。正确的 ?
    去年,我遇到了类似的问题(100万个顶点)。我最终选择发送更多的绘图调用,而不是使用复杂的着色器。是的,绑定(bind)大量数据(16个纹理绑定(bind)!)会减慢此类设备的速度。



    在iPad 2上,屏幕上的1000k顶点(每个顶点的数据量比您多)的渲染速度应更快:超过20 fps。

    看来您的大多数数据都是静态的。 您可以尝试为每个纹理建立一个vbo或索引列表(我不知道这是更快的),可以大大简化您的 fragment 着色器。

  • 将vbo与所有“静态数据”(顶点位置,纹理坐标)绑定(bind)
    每种纹理的

  • 绑定(bind)纹理
  • 将glDrawElements与“特定纹理”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,则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:低处到处都是危险的。尝试中级。

    祝您好运,您正在达到设备极限!

    10-06 04:09
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