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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
#include "ScreenAlignedQuad.h"
#include <cassert>
#include <array>
#include <glm/vec2.hpp>
#include <glbinding/gl/enum.h>
#include <glbinding/gl/functions.h>
#include <globjects/base/StaticStringSource.h>
#include <globjects/Program.h>
#include <globjects/VertexArray.h>
#include <globjects/Texture.h>
#include <globjects/VertexAttributeBinding.h>
#include <globjects/Buffer.h>
#include <globjects/Shader.h>
#include <globjects/base/StringTemplate.h>
using namespace gl;
using namespace glm;
using namespace globjects;
const char * ScreenAlignedQuad::s_defaultVertexShaderSource = R"(
#version 140
#extension GL_ARB_explicit_attrib_location : require
layout (location = 0) in vec2 a_vertex;
out vec2 v_uv;
void main()
{
v_uv = a_vertex * 0.5 + 0.5;
gl_Position = vec4(a_vertex, 0.0, 1.0);
}
)";
const char * ScreenAlignedQuad::s_defaultFagmentShaderSource = R"(
#version 140
#extension GL_ARB_explicit_attrib_location : require
uniform sampler2D source;
layout (location = 0) out vec4 fragColor;
in vec2 v_uv;
void main()
{
fragColor = texture(source, v_uv);
}
)";
ScreenAlignedQuad::ScreenAlignedQuad(
Shader * fragmentShader
, Texture * texture)
: m_vertexShader (nullptr)
, m_fragmentShader(fragmentShader)
, m_program(new Program())
, m_texture(texture)
, m_samplerIndex(0)
{
StringTemplate * vertexShaderSource = new StringTemplate(new StaticStringSource(s_defaultVertexShaderSource));
StringTemplate * fragmentShaderSource = new StringTemplate(new StaticStringSource(s_defaultFagmentShaderSource));
m_vertexShader = new Shader(GL_VERTEX_SHADER, vertexShaderSource);
if (!m_fragmentShader)
m_fragmentShader = new Shader(GL_FRAGMENT_SHADER, fragmentShaderSource);
m_program->attach(m_vertexShader, m_fragmentShader);
initialize();
}
ScreenAlignedQuad::ScreenAlignedQuad(Shader * fragmentShader)
: ScreenAlignedQuad(fragmentShader, nullptr)
{
}
ScreenAlignedQuad::ScreenAlignedQuad(Texture * texture)
: ScreenAlignedQuad(nullptr, texture)
{
}
ScreenAlignedQuad::ScreenAlignedQuad(Program * program)
: m_vertexShader(nullptr)
, m_fragmentShader(nullptr)
, m_program(program)
, m_texture(nullptr)
, m_samplerIndex(0)
{
assert(program != nullptr);
initialize();
}
void ScreenAlignedQuad::initialize()
{
// By default, counterclockwise polygons are taken to be front-facing.
// http://www.opengl.org/sdk/docs/man/xhtml/glFrontFace.xml
static const std::array<vec2, 4> raw { { vec2(+1.f,-1.f), vec2(+1.f,+1.f), vec2(-1.f,-1.f), vec2(-1.f,+1.f) } };
m_vao = new VertexArray;
m_buffer = new Buffer();
m_buffer->setData(raw, GL_STATIC_DRAW); //needed for some drivers
auto binding = m_vao->binding(0);
binding->setAttribute(0);
binding->setBuffer(m_buffer, 0, sizeof(vec2));
binding->setFormat(2, GL_FLOAT, GL_FALSE, 0);
m_vao->enable(0);
setSamplerUniform(0);
}
void ScreenAlignedQuad::draw()
{
if (m_texture)
{
glActiveTexture(GL_TEXTURE0 + m_samplerIndex);
m_texture->bind();
}
m_program->use();
m_vao->drawArrays(GL_TRIANGLE_STRIP, 0, 4);
m_program->release();
if (m_texture)
m_texture->unbind();
}
void ScreenAlignedQuad::setTexture(Texture* texture)
{
m_texture = texture;
}
void ScreenAlignedQuad::setSamplerUniform(int index)
{
m_samplerIndex = index;
m_program->setUniform("source", m_samplerIndex);
}
Program * ScreenAlignedQuad::program()
{
return m_program;
}
Shader * ScreenAlignedQuad::vertexShader()
{
return m_vertexShader;
}
Shader * ScreenAlignedQuad::fragmentShader()
{
return m_fragmentShader;
}
|
