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#include "shader/texture-blit-vert.h"
  32#include "shader/texture-blit-flip-vert.h"
  33#include "shader/texture-blit-frag.h"
  34
  35struct QemuGLShader {
  36    GLint texture_blit_prog;
  37    GLint texture_blit_flip_prog;
  38    GLint texture_blit_vao;
  39};
  40
  41/* ---------------------------------------------------------------------- */
  42
  43static GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog)
  44{
  45    static const GLfloat in_position[] = {
  46        -1, -1,
  47        1,  -1,
  48        -1,  1,
  49        1,   1,
  50    };
  51    GLint l_position;
  52    GLuint vao, buffer;
  53
  54    glGenVertexArrays(1, &vao);
  55    glBindVertexArray(vao);
  56
  57    /* this is the VBO that holds the vertex data */
  58    glGenBuffers(1, &buffer);
  59    glBindBuffer(GL_ARRAY_BUFFER, buffer);
  60    glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position,
  61                 GL_STATIC_DRAW);
  62
  63    l_position = glGetAttribLocation(texture_blit_prog, "in_position");
  64    glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0);
  65    glEnableVertexAttribArray(l_position);
  66
  67    glBindBuffer(GL_ARRAY_BUFFER, 0);
  68    glBindVertexArray(0);
  69
  70    return vao;
  71}
  72
  73void qemu_gl_run_texture_blit(QemuGLShader *gls, bool flip)
  74{
  75    glUseProgram(flip
  76                 ? gls->texture_blit_flip_prog
  77                 : gls->texture_blit_prog);
  78    glBindVertexArray(gls->texture_blit_vao);
  79    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  80}
  81
  82/* ---------------------------------------------------------------------- */
  83
  84static GLuint qemu_gl_create_compile_shader(GLenum type, const GLchar *src)
  85{
  86    GLuint shader;
  87    GLint status, length;
  88    char *errmsg;
  89
  90    shader = glCreateShader(type);
  91    glShaderSource(shader, 1, &src, 0);
  92    glCompileShader(shader);
  93
  94    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  95    if (!status) {
  96        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
  97        errmsg = g_malloc(length);
  98        glGetShaderInfoLog(shader, length, &length, errmsg);
  99        fprintf(stderr, "%s: compile %s error\n%s\n", __func__,
 100                (type == GL_VERTEX_SHADER) ? "vertex" : "fragment",
 101                errmsg);
 102        g_free(errmsg);
 103        return 0;
 104    }
 105    return shader;
 106}
 107
 108static GLuint qemu_gl_create_link_program(GLuint vert, GLuint frag)
 109{
 110    GLuint program;
 111    GLint status, length;
 112    char *errmsg;
 113
 114    program = glCreateProgram();
 115    glAttachShader(program, vert);
 116    glAttachShader(program, frag);
 117    glLinkProgram(program);
 118
 119    glGetProgramiv(program, GL_LINK_STATUS, &status);
 120    if (!status) {
 121        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
 122        errmsg = g_malloc(length);
 123        glGetProgramInfoLog(program, length, &length, errmsg);
 124        fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
 125        g_free(errmsg);
 126        return 0;
 127    }
 128    return program;
 129}
 130
 131static GLuint qemu_gl_create_compile_link_program(const GLchar *vert_src,
 132                                                  const GLchar *frag_src)
 133{
 134    GLuint vert_shader, frag_shader, program;
 135
 136    vert_shader = qemu_gl_create_compile_shader(GL_VERTEX_SHADER, vert_src);
 137    frag_shader = qemu_gl_create_compile_shader(GL_FRAGMENT_SHADER, frag_src);
 138    if (!vert_shader || !frag_shader) {
 139        return 0;
 140    }
 141
 142    program = qemu_gl_create_link_program(vert_shader, frag_shader);
 143    glDeleteShader(vert_shader);
 144    glDeleteShader(frag_shader);
 145
 146    return program;
 147}
 148
 149/* ---------------------------------------------------------------------- */
 150
 151QemuGLShader *qemu_gl_init_shader(void)
 152{
 153    QemuGLShader *gls = g_new0(QemuGLShader, 1);
 154
 155    gls->texture_blit_prog = qemu_gl_create_compile_link_program
 156        (texture_blit_vert_src, texture_blit_frag_src);
 157    gls->texture_blit_flip_prog = qemu_gl_create_compile_link_program
 158        (texture_blit_flip_vert_src, texture_blit_frag_src);
 159    if (!gls->texture_blit_prog || !gls->texture_blit_flip_prog) {
 160        exit(1);
 161    }
 162
 163    gls->texture_blit_vao =
 164        qemu_gl_init_texture_blit(gls->texture_blit_prog);
 165
 166    return gls;
 167}
 168
 169void qemu_gl_fini_shader(QemuGLShader *gls)
 170{
 171    if (!gls) {
 172        return;
 173    }
 174    g_free(gls);
 175}
 176