LXR qemu/ui/shader.c

   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/osdep.h"
  28#include "qemu-common.h"
  29#include "ui/shader.h"
  30
  31/* ---------------------------------------------------------------------- */
  32
  33GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog)
  34{
  35    static const GLfloat in_position[] = {
  36        -1, -1,
  37        1,  -1,
  38        -1,  1,
  39        1,   1,
  40    };
  41    GLint l_position;
  42    GLuint vao, buffer;
  43
  44    glGenVertexArrays(1, &vao);
  45    glBindVertexArray(vao);
  46
  47    /* this is the VBO that holds the vertex data */
  48    glGenBuffers(1, &buffer);
  49    glBindBuffer(GL_ARRAY_BUFFER, buffer);
  50    glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position,
  51                 GL_STATIC_DRAW);
  52
  53    l_position = glGetAttribLocation(texture_blit_prog, "in_position");
  54    glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0);
  55    glEnableVertexAttribArray(l_position);
  56
  57    glBindBuffer(GL_ARRAY_BUFFER, 0);
  58    glBindVertexArray(0);
  59
  60    return vao;
  61}
  62
  63void qemu_gl_run_texture_blit(GLint texture_blit_prog,
  64                              GLint texture_blit_vao)
  65{
  66    glUseProgram(texture_blit_prog);
  67    glBindVertexArray(texture_blit_vao);
  68    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  69}
  70
  71/* ---------------------------------------------------------------------- */
  72
  73GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src)
  74{
  75    GLuint shader;
  76    GLint status, length;
  77    char *errmsg;
  78
  79    shader = glCreateShader(type);
  80    glShaderSource(shader, 1, &src, 0);
  81    glCompileShader(shader);
  82
  83    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  84    if (!status) {
  85        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
  86        errmsg = malloc(length);
  87        glGetShaderInfoLog(shader, length, &length, errmsg);
  88        fprintf(stderr, "%s: compile %s error\n%s\n", __func__,
  89                (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
  90                errmsg);
  91        free(errmsg);
  92        return 0;
  93    }
  94    return shader;
  95}
  96
  97GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag)
  98{
  99    GLuint program;
 100    GLint status, length;
 101    char *errmsg;
 102
 103    program = glCreateProgram();
 104    glAttachShader(program, vert);
 105    glAttachShader(program, frag);
 106    glLinkProgram(program);
 107
 108    glGetProgramiv(program, GL_LINK_STATUS, &status);
 109    if (!status) {
 110        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
 111        errmsg = malloc(length);
 112        glGetProgramInfoLog(program, length, &length, errmsg);
 113        fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
 114        free(errmsg);
 115        return 0;
 116    }
 117    return program;
 118}
 119
 120GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
 121                                           const GLchar *frag_src)
 122{
 123    GLuint vert_shader, frag_shader, program;
 124
 125    vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
 126    frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
 127    if (!vert_shader || !frag_shader) {
 128        return 0;
 129    }
 130
 131    program = qemu_gl_create_link_program(vert_shader, frag_shader);
 132    glDeleteShader(vert_shader);
 133    glDeleteShader(frag_shader);
 134
 135    return program;
 136}
 137