android NDK 可能实现最快的 2D 帧速率，我的尝试包括在内，有更好的选择吗？

android NDK 可能实现最快的 2D 帧速率，我的尝试包括在内，有更好的选择吗？

我使用 NDK 和 OpenGL ES 2.0 将帧显示为 GL_TRIANGLE_STRIP 上的纹理。 这是在 HTC Desire 上完成的，其硬件与 Nexus One 相同。 我尝试加载多个 GL_RGBA 纹理并在纹理之间切换，因为单个纹理的正常填充率低得令人失望：

• 1 个纹理：4.78 fps
• 2 个纹理：19.68 fps
• 3 个纹理：20.18 fps
• 4 个纹理：28.52 fps
• 5 个纹理：29.01 fps
• 6 个纹理：30.32 fps

我认为即使 30.32 fps RGBA 仍然太慢。

那么这是实现最快 2D 帧速率（相同质量）的方法吗？ 有什么建议可以加快速度吗？

这是相关代码，它基于 hello-gl2 NDK 示例：

=== GL2JNIView.java :

init(false, 0, 0);
ConfigChooser(5, 6, 5, 0, depth, stencil);

=== gl_code.cpp ：

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

#include <android/log.h>

#include <stdlib.h>
#include <time.h>

typedef unsigned char byte;

static int view_width, view_height;
static byte* framebuffer;
static int framebuffer_size;
static GLuint texture_id[6];
static const char* vertexSrc =
 "precision highp float;\n"
 "precision highp int;\n"
 "attribute vec4 vertexCoords;\n"
 "attribute vec2 textureCoords;\n"
 "varying vec2 f_textureCoords;\n"
 "void main() {\n"
 "  f_textureCoords = textureCoords;\n"
 "  gl_Position = vertexCoords;\n"
 "}\n";
static const char* fragmentSrc  =
 "precision highp float;\n"
 "precision highp int;\n"
 "uniform sampler2D texture;\n"
 "varying vec2 f_textureCoords;\n"
 "void main() {\n"
 "  gl_FragColor = texture2D(texture, f_textureCoords);\n"
 "}\n";
static GLuint shaderProgram;
static GLint attrib_vertexCoords;
static GLint attrib_textureCoords;
static GLint uniform_texture;
static const GLfloat vertexCoords[] = {-1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0};
static const GLfloat textureCoords[] = {0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 1.0, 1.0};

JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_init(JNIEnv * env, jobject obj,  jint width, jint height) {
 view_width = width;
 view_height = height;

 framebuffer_size = 4*view_width*view_height;
 framebuffer = (byte*)calloc(framebuffer_size, sizeof(byte));
 for (int i = 0; i < framebuffer_size; i++) framebuffer[i] = 0;

 glViewport(0, 0, view_width, view_height);

 glGenTextures(6, &texture_id[0]);
 glActiveTexture(GL_TEXTURE0);
 glBindTexture(GL_TEXTURE_2D, texture_id[0]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glActiveTexture(GL_TEXTURE1);
 glBindTexture(GL_TEXTURE_2D, texture_id[1]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glActiveTexture(GL_TEXTURE2);
 glBindTexture(GL_TEXTURE_2D, texture_id[2]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glActiveTexture(GL_TEXTURE3);
 glBindTexture(GL_TEXTURE_2D, texture_id[3]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glActiveTexture(GL_TEXTURE4);
 glBindTexture(GL_TEXTURE_2D, texture_id[4]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glActiveTexture(GL_TEXTURE5);
 glBindTexture(GL_TEXTURE_2D, texture_id[5]);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);

 shaderProgram = glCreateProgram();
  GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vertexShader, 1, &vertexSrc, NULL);
  glCompileShader(vertexShader);
 glAttachShader(shaderProgram, vertexShader);
  GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fragmentShader, 1, &fragmentSrc, NULL);
  glCompileShader(fragmentShader);
 glAttachShader(shaderProgram, fragmentShader);
 glLinkProgram(shaderProgram);
 glUseProgram(shaderProgram);

 uniform_texture = glGetUniformLocation(shaderProgram, "texture");
 glUniform1i(uniform_texture, 0);

 attrib_vertexCoords = glGetAttribLocation(shaderProgram, "vertexCoords");
 glEnableVertexAttribArray(attrib_vertexCoords);
 glVertexAttribPointer(attrib_vertexCoords, 2, GL_FLOAT, GL_FALSE, 0, vertexCoords);

 attrib_textureCoords = glGetAttribLocation(shaderProgram, "textureCoords");
 glEnableVertexAttribArray(attrib_textureCoords);
 glVertexAttribPointer(attrib_textureCoords, 2, GL_FLOAT, GL_FALSE, 0, textureCoords);
}

JNIEXPORT void JNICALL Java_com_android_gl2jni_GL2JNILib_step(JNIEnv * env, jobject obj) {
 static int frame_count = 0;
 static clock_t last_time = clock();
 static int last_frame_count = 0;

 frame_count++;
 if (clock()-last_time > 1e7) {
  __android_log_print(ANDROID_LOG_INFO, "libgl2jni", "fps: %f", ((float)frame_count-last_frame_count)/(clock()-last_time)*1e6);
  last_time = clock();
  last_frame_count = frame_count;
 }

 static byte val = 0;
 val++;
 if (val == 256) val = 0;
 for (int i = 0; i < framebuffer_size; i++) framebuffer[i] = val;

 int tst = frame_count%6;
 if (tst == 0) {
  glActiveTexture(GL_TEXTURE0);
 } else if (tst == 1) {
  glActiveTexture(GL_TEXTURE1);
 } else if (tst == 2) {
  glActiveTexture(GL_TEXTURE2);
 } else if (tst == 3) {
  glActiveTexture(GL_TEXTURE3);
 } else if (tst == 4) {
  glActiveTexture(GL_TEXTURE4);
 } else if (tst == 5) {
  glActiveTexture(GL_TEXTURE5);
 }
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);
 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}

我意识到你的问题相当老了，你可能已经解决了它或转向其他问题，但如果其他人遇到这个问题，我会给出建议。

首先，glTexImage2D要求图形子系统在每次调用它时执行纹理对象的内存释放和重新分配，因为纹理参数可能会在调用之间发生变化。优化的驱动程序可能会查看宽度、高度和格式，如果它们都相同，则可以跳过重新分配，但 Android 驱动程序实现者实际上不太可能这样做。

为了完全避免纹理重新分配，您可以使用glTexSubImage2D替换完整位图或其中的一部分。如果将其与上述纹理缓冲方案结合起来，您应该会看到相当大的速度提升。您甚至可以扩展它来检测显示器的修改区域，并仅更新帧之间已更改的矩形部分。

总而言之，将纹理初始化代码更改为调用glTexImage2D使用 NULL 位图指针，因此 OpenGL 只为纹理分配内存，并且实际上不会将任何数据复制到其中，如下所示：

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, view_width, view_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

然后使用以下命令更新游戏循环中的每一帧：

glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, view_width, view_height, GL_RGBA, GL_UNSIGNED_BYTE, framebuffer);