Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170103-1' into staging
[qemu.git] / 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
33 GLuint 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
63 void 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
73 GLuint 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 = g_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 g_free(errmsg);
92 return 0;
93 }
94 return shader;
95 }
96
97 GLuint 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 = g_malloc(length);
112 glGetProgramInfoLog(program, length, &length, errmsg);
113 fprintf(stderr, "%s: link program: %s\n", __func__, errmsg);
114 g_free(errmsg);
115 return 0;
116 }
117 return program;
118 }
119
120 GLuint 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 }