Steward
分享是一種喜悅、更是一種幸福
掌機 - Anbernic RG28XX - C/C++ - OpenGL ES 2.0 - Draw Texture
參考資訊:
https://docs.gl/es2/glTexSubImage2D
https://learnopengl.com/Getting-started/Textures
https://www.khronos.org/assets/uploads/books/openglr_es_20_programming_guide_sample.pdf
main.c
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> #include <dlfcn.h> #include <unistd.h> #include <EGL/egl.h> #include <GLES2/gl2.h> #define LCD_W 480 #define LCD_H 640 const char *vShaderSrc = "attribute vec4 a_position; \n" "attribute vec2 a_texCoord; \n" "varying vec2 v_texCoord; \n" "void main() \n" "{ \n" " gl_Position = a_position; \n" " v_texCoord = a_texCoord; \n" "} \n" ; const char *fShaderSrc = "precision mediump float; \n" "varying vec2 v_texCoord; \n" "uniform sampler2D s_texture; \n" "void main() \n" "{ \n" " vec3 tex = texture2D(s_texture, v_texCoord).rgb; \n" " gl_FragColor = vec4(tex, 1.0); \n" "} \n" ; int main ( int argc, char ** argv) { EGLint egl_major = 0; EGLint egl_minor = 0; EGLint num_configs = 0; EGLConfig configs = {0}; EGLDisplay display = EGL_NO_DISPLAY ; EGLSurface surface = EGL_NO_SURFACE ; EGLContext context = EGL_NO_CONTEXT ; EGLint config_attribs[] = { EGL_SURFACE_TYPE , EGL_WINDOW_BIT , EGL_RENDERABLE_TYPE , EGL_OPENGL_ES2_BIT , EGL_RED_SIZE , 8, EGL_GREEN_SIZE , 8, EGL_BLUE_SIZE , 8, EGL_ALPHA_SIZE , 8, EGL_NONE }; EGLint window_attributes[] = { EGL_RENDER_BUFFER , EGL_BACK_BUFFER , EGL_NONE }; EGLint const context_attributes[] = { EGL_CONTEXT_CLIENT_VERSION , 2, EGL_NONE , }; GLuint vShader = 0; GLuint fShader = 0; GLuint pObject = 0; GLint compiled = 0; int x = 0; int y = 0; uint32_t *p = NULL ; GLuint texID = 0; GLubyte *buf = NULL ; GLfloat vVertices[] = { -1.0f, 1.0f, 0.0f, 0.0f, 0.0f, -1.0f, -1.0f, 0.0f, 0.0f, 1.0f, 1.0f, -1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f }; GLushort indices[] = {0, 1, 2, 0, 2, 3}; display = eglGetDisplay ( EGL_DEFAULT_DISPLAY ); eglInitialize ( display , &egl_major, &egl_minor); eglChooseConfig ( display , config_attribs, &configs, 1, &num_configs); surface = eglCreateWindowSurface ( display , configs, 0, window_attributes); context = eglCreateContext ( display , configs, EGL_NO_CONTEXT , context_attributes); eglMakeCurrent ( display , surface, surface, context ); vShader = glCreateShader ( GL_VERTEX_SHADER ); glShaderSource (vShader, 1, &vShaderSrc, NULL ); glCompileShader (vShader); glGetShaderiv (vShader, GL_COMPILE_STATUS , &compiled); fShader = glCreateShader ( GL_FRAGMENT_SHADER ); glShaderSource (fShader, 1, &fShaderSrc, NULL ); glCompileShader (fShader); glGetShaderiv (fShader, GL_COMPILE_STATUS , &compiled); pObject = glCreateProgram (); glAttachShader (pObject, vShader); glAttachShader (pObject, fShader); glLinkProgram (pObject); glUseProgram (pObject); GLint posLoc = glGetAttribLocation (pObject, "a_position" ); GLint texLoc = glGetAttribLocation (pObject, "a_texCoord" ); GLint samLoc = glGetUniformLocation (pObject, "s_texture" ); glGenTextures (1, &texID); glViewport (0, 0, LCD_W , LCD_H ); glClearColor (0.0f, 0.0f, 0.0f, 1.0f); glClear ( GL_COLOR_BUFFER_BIT ); uint32_t col[] = {0xffff0000, 0xff00ff00, 0xff0000ff}; buf = malloc ( LCD_W * LCD_H * 4); p = ( uint32_t *)buf; for (y = 0; y < LCD_H ; y++) { for (x = 0; x < LCD_W ; x++) { *p++ = col[x / 160]; } } glBindTexture ( GL_TEXTURE_2D , texID); glPixelStorei ( GL_UNPACK_ALIGNMENT , 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 , LCD_W , LCD_H , 0, GL_RGBA , GL_UNSIGNED_BYTE , buf); glActiveTexture ( GL_TEXTURE0 ); glBindTexture ( GL_TEXTURE_2D , texID); glVertexAttribPointer (posLoc, 3, GL_FLOAT , GL_FALSE , 5 * sizeof ( GLfloat ), vVertices); glVertexAttribPointer (texLoc, 2, GL_FLOAT , GL_FALSE , 5 * sizeof ( GLfloat ), &vVertices[3]); glEnableVertexAttribArray (posLoc); glEnableVertexAttribArray (texLoc); glUniform1i (samLoc, 0); glDrawElements ( GL_TRIANGLES , 6, GL_UNSIGNED_SHORT , indices); eglSwapBuffers ( display , surface); sleep (3); free (buf); glDeleteTextures (1, &texID); eglMakeCurrent ( display , EGL_NO_SURFACE , EGL_NO_SURFACE , EGL_NO_CONTEXT ); eglDestroyContext ( display , context ); eglDestroySurface ( display , surface); eglTerminate ( display ); return 0; } |
編譯
$ /opt/a30/bin/arm-linux-gcc main.c -o test -lGLESv2 -lEGL -ldl
完成