1 /* 2 * QEMU opengl shader helper functions 3 * 4 * Copyright (c) 2014 Red Hat 5 * 6 * Authors: 7 * Gerd Hoffmann <kraxel@redhat.com> 8 * 9 * Permission is hereby granted, free of charge, to any person obtaining a copy 10 * of this software and associated documentation files (the "Software"), to deal 11 * in the Software without restriction, including without limitation the rights 12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 13 * copies of the Software, and to permit persons to whom the Software is 14 * furnished to do so, subject to the following conditions: 15 * 16 * The above copyright notice and this permission notice shall be included in 17 * all copies or substantial portions of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 25 * THE SOFTWARE. 26 */ 27 #include "qemu-common.h" 28 #include "ui/shader.h" 29 30 /* ---------------------------------------------------------------------- */ 31 32 GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog) 33 { 34 static const GLfloat in_position[] = { 35 -1, -1, 36 1, -1, 37 -1, 1, 38 1, 1, 39 }; 40 GLint l_position; 41 GLuint vao, buffer; 42 43 glGenVertexArrays(1, &vao); 44 glBindVertexArray(vao); 45 46 /* this is the VBO that holds the vertex data */ 47 glGenBuffers(1, &buffer); 48 glBindBuffer(GL_ARRAY_BUFFER, buffer); 49 glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position, 50 GL_STATIC_DRAW); 51 52 l_position = glGetAttribLocation(texture_blit_prog, "in_position"); 53 glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0); 54 glEnableVertexAttribArray(l_position); 55 56 glBindBuffer(GL_ARRAY_BUFFER, 0); 57 glBindVertexArray(0); 58 59 return vao; 60 } 61 62 void qemu_gl_run_texture_blit(GLint texture_blit_prog, 63 GLint texture_blit_vao) 64 { 65 glUseProgram(texture_blit_prog); 66 glBindVertexArray(texture_blit_vao); 67 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); 68 } 69 70 /* ---------------------------------------------------------------------- */ 71 72 GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src) 73 { 74 GLuint shader; 75 GLint status, length; 76 char *errmsg; 77 78 shader = glCreateShader(type); 79 glShaderSource(shader, 1, &src, 0); 80 glCompileShader(shader); 81 82 glGetShaderiv(shader, GL_COMPILE_STATUS, &status); 83 if (!status) { 84 glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length); 85 errmsg = malloc(length); 86 glGetShaderInfoLog(shader, length, &length, errmsg); 87 fprintf(stderr, "%s: compile %s error\n%s\n", __func__, 88 (type == GL_VERTEX_SHADER) ? "vertex" : "fragment", 89 errmsg); 90 free(errmsg); 91 return 0; 92 } 93 return shader; 94 } 95 96 GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag) 97 { 98 GLuint program; 99 GLint status, length; 100 char *errmsg; 101 102 program = glCreateProgram(); 103 glAttachShader(program, vert); 104 glAttachShader(program, frag); 105 glLinkProgram(program); 106 107 glGetProgramiv(program, GL_LINK_STATUS, &status); 108 if (!status) { 109 glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length); 110 errmsg = malloc(length); 111 glGetProgramInfoLog(program, length, &length, errmsg); 112 fprintf(stderr, "%s: link program: %s\n", __func__, errmsg); 113 free(errmsg); 114 return 0; 115 } 116 return program; 117 } 118 119 GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src, 120 const GLchar *frag_src) 121 { 122 GLuint vert_shader, frag_shader, program; 123 124 vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src); 125 frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src); 126 if (!vert_shader || !frag_shader) { 127 return 0; 128 } 129 130 program = qemu_gl_create_link_program(vert_shader, frag_shader); 131 glDeleteShader(vert_shader); 132 glDeleteShader(frag_shader); 133 134 return program; 135 } 136