/
gltoy.go
179 lines (144 loc) · 3.22 KB
/
gltoy.go
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
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
package main
import (
"github.com/banthar/Go-SDL/sdl"
"github.com/banthar/gl"
"github.com/shogg/glfps"
"io/ioutil"
)
type vec3 [3]float32
type vec2 [2]float32
var (
width, height = 640, 480
prg0 = gl.Program(0)
prg gl.Program
vertices = []vec3 {
{-1.3,-1.0,-1.0}, // 0 2--3
{ 1.3,-1.0,-1.0}, // 1 |\ |
{-1.3, 1.0,-1.0}, // 2 | \|
{ 1.3, 1.0,-1.0}, // 3 0--1
}
texCoords = []vec2 {
{ 0.0, 0.0}, // 0 2--3
{ 1.3, 0.0}, // 1 |\ |
{ 0.0, 1.0}, // 2 | \|
{ 1.3, 1.0}, // 3 0--1
}
vertexShaderSrc = `
varying vec2 vTexCoord;
uniform vec2 resolution;
uniform float time;
void main()
{
vTexCoord = vec2(gl_MultiTexCoord0) * 2.0 - 1.0;
gl_Position = ftransform();
}`
)
func main() {
sdl.Init(sdl.INIT_VIDEO)
defer sdl.Quit()
screen := sdl.SetVideoMode(width, height, 32, sdl.OPENGL)
if screen == nil {
panic("Couldn't set video mode: " + sdl.GetError() + "\n")
}
if err := gl.Init(); err != 0 {
panic("gl error")
}
initGl()
initShaders()
mainLoop()
}
func initShaders() {
// Compile vertex shader
vshader := gl.CreateShader(gl.VERTEX_SHADER)
vshader.Source(vertexShaderSrc)
vshader.Compile()
if vshader.Get(gl.COMPILE_STATUS) != gl.TRUE {
panic("vertex shader compile error: " + vshader.GetInfoLog())
}
// Compile fragment shader
fshader := gl.CreateShader(gl.FRAGMENT_SHADER)
fragSrc, err := readShader("dist-field-raycaster.glsl")
if err != nil {
panic(err)
}
fshader.Source(fragSrc)
fshader.Compile()
if fshader.Get(gl.COMPILE_STATUS) != gl.TRUE {
panic("fragment shader compile error: " + fshader.GetInfoLog())
}
// Link program
prg = gl.CreateProgram()
prg.AttachShader(vshader)
prg.AttachShader(fshader)
prg.Link()
if prg.Get(gl.LINK_STATUS) != gl.TRUE {
panic("linker error: " + prg.GetInfoLog())
}
prg.Use()
}
func readShader(filename string) (s string, err error) {
data, err := ioutil.ReadFile(filename)
if err != nil { return }
s = string(data)
return
}
func initGl() {
h := float64(height) / float64(width)
gl.Viewport(0, 0, width, height)
gl.MatrixMode(gl.PROJECTION)
gl.LoadIdentity()
gl.Frustum(-1.0, 1.0, -h, h, 5.0, 60.0)
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
gl.Translatef(0.0, 0.0, -6.0)
gl.EnableClientState(gl.VERTEX_ARRAY)
gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
gl.VertexPointer(3, 0, &vertices[0][0])
gl.TexCoordPointer(2, 0, &texCoords[0][0])
}
func draw() {
t := float32(sdl.GetTicks()) / 500.0
time := prg.GetUniformLocation("time")
time.Uniform1f(t)
gl.Clear(gl.COLOR_BUFFER_BIT)
gl.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)
if gl.GetError() != gl.NO_ERROR {
panic("draw error")
}
}
func drawOverlay() {
prg0.Use()
glfps.Draw(10, 10)
prg.Use()
}
func mainLoop() {
done := false
for !done {
for e := sdl.PollEvent(); e != nil; e = sdl.PollEvent() {
switch e.(type) {
case *sdl.QuitEvent:
done = true
break
case *sdl.KeyboardEvent:
key := e.(*sdl.KeyboardEvent).Keysym.Sym
if key == sdl.K_RETURN {
done = true
break
} else {
handleKey(key)
}
}
}
draw()
drawOverlay()
sdl.GL_SwapBuffers()
}
}
func handleKey(key uint32) {
switch key {
case sdl.K_LEFT:
case sdl.K_RIGHT:
case sdl.K_UP:
case sdl.K_DOWN:
}
}