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jackmottjackmott
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hello triangle
1 parent 69ec988 commit 8530765

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2 files changed

+237
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lines changed

2 files changed

+237
-0
lines changed

‎hellotriangle/hellotriangle.go‎

Lines changed: 133 additions & 0 deletions
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package main
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import (
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"fmt"
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"github.com/go-gl/gl/v3.3-core/gl"
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"github.com/veandco/go-sdl2/sdl"
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"strings"
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)
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const winWidth = 1280
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const winHeight = 720
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func main() {
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err := sdl.Init(sdl.INIT_EVERYTHING)
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if err != nil {
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panic(err)
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}
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defer sdl.Quit()
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window, err := sdl.CreateWindow("Hello Triangle", 200, 200, winWidth, winHeight, sdl.WINDOW_OPENGL)
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if err != nil {
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panic(err)
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}
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window.GLCreateContext()
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defer window.Destroy()
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gl.Init()
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version := gl.GoStr(gl.GetString(gl.VERSION))
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fmt.Println("OpenGL Version", version)
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//TODO - why is the csource string not getting freed?
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fragmentShaderSource :=
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`#version 330 core
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out vec4 FragColor;
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void main()
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{
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FragColor = vec4(1.0f, 0.0f, 0.0f, 1.0f);
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} `
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fmt.Println(fragmentShaderSource)
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fragmentShader := gl.CreateShader(gl.FRAGMENT_SHADER)
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csource, free := gl.Strs(fragmentShaderSource)
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gl.ShaderSource(fragmentShader, 1, csource, nil)
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gl.CompileShader(fragmentShader)
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free()
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var status int32
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gl.GetShaderiv(fragmentShader, gl.COMPILE_STATUS, &status)
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if status == gl.FALSE {
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var logLength int32
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gl.GetShaderiv(fragmentShader, gl.INFO_LOG_LENGTH, &logLength)
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log := strings.Repeat("\x00", int(logLength+1))
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gl.GetShaderInfoLog(fragmentShader, logLength, nil, gl.Str(log))
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panic("Failed to compile fragment shader: \n" + log)
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}
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vertexShaderSource :=
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`#version 330 core
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layout (location = 0) in vec3 aPos;
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void main()
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{
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gl_Position = vec4(aPos.x,aPos.y,aPos.z,1.0);
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}`
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vertexShader := gl.CreateShader(gl.VERTEX_SHADER)
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csource, free = gl.Strs(vertexShaderSource)
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gl.ShaderSource(vertexShader, 1, csource, nil)
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free()
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gl.CompileShader(vertexShader)
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gl.GetShaderiv(vertexShader, gl.COMPILE_STATUS, &status)
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if status == gl.FALSE {
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var logLength int32
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gl.GetShaderiv(vertexShader, gl.INFO_LOG_LENGTH, &logLength)
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log := strings.Repeat("\x00", int(logLength+1))
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gl.GetShaderInfoLog(vertexShader, logLength, nil, gl.Str(log))
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panic("Failed to compile vertex shader: \n" + log)
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}
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shaderProgram := gl.CreateProgram()
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gl.AttachShader(shaderProgram, vertexShader)
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gl.AttachShader(shaderProgram, fragmentShader)
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gl.LinkProgram(shaderProgram)
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var success int32
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gl.GetProgramiv(shaderProgram, gl.LINK_STATUS, &success)
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if success == gl.FALSE {
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var logLength int32
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gl.GetProgramiv(shaderProgram, gl.INFO_LOG_LENGTH, &logLength)
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log := strings.Repeat("\x00", int(logLength+1))
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gl.GetProgramInfoLog(shaderProgram, logLength, nil, gl.Str(log))
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panic("Failed to link program: \n" + log)
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}
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gl.DeleteShader(vertexShader)
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gl.DeleteShader(fragmentShader)
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vertices := []float32{
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-0.5, -0.5, 0.0,
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0.5, -0.5, 0.0,
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0.0, 0.5, 0.0}
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var VBO uint32
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gl.GenBuffers(1, &VBO)
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gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
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var VAO uint32
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gl.GenVertexArrays(1, &VAO)
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gl.BindVertexArray(VAO)
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gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, gl.Ptr(vertices), gl.STATIC_DRAW)
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gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 3*4, nil)
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gl.EnableVertexAttribArray(0)
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gl.BindVertexArray(0)
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for {
116+
for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
117+
switch event.(type) {
118+
case *sdl.QuitEvent:
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return
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}
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}
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gl.ClearColor(0.0, 0.0, 0.0, 0.0)
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gl.Clear(gl.COLOR_BUFFER_BIT)
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gl.UseProgram(shaderProgram)
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gl.BindVertexArray(VAO)
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gl.DrawArrays(gl.TRIANGLES, 0, 3)
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window.GLSwap()
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}
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}

‎opengltest/test.go‎

Lines changed: 104 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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package main
2+
3+
import (
4+
"fmt"
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"github.com/go-gl/gl/v3.3-core/gl"
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"github.com/veandco/go-sdl2/sdl"
7+
"strings"
8+
"unsafe"
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)
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11+
const winWidth = 1280
12+
const winHeight = 720
13+
14+
func main() {
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16+
err := sdl.Init(sdl.INIT_EVERYTHING)
17+
if err != nil {
18+
fmt.Println(err)
19+
return
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}
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defer sdl.Quit()
22+
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window, err := sdl.CreateWindow("OpenGL", 200, 200,
24+
int32(winWidth), int32(winHeight), sdl.WINDOW_OPENGL)
25+
if err != nil {
26+
fmt.Println(err)
27+
return
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}
29+
window.GLCreateContext()
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defer window.Destroy()
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fmt.Println("A")
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gl.Init()
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fmt.Println("B")
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version := gl.GoStr(gl.GetString(gl.VERSION))
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fmt.Println("OpenGL version", version)
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vertices := []float32{
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0.5, 0.5, 0.0,
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0.5, -0.5, 0.0,
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-0.5, -0.5, 0.0,
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-0.5, 0.5, 0.0}
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var VBO uint32
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gl.GenBuffers(1, &VBO)
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gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
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gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*int(unsafe.Sizeof(vertices[0])), gl.Ptr(vertices), gl.STATIC_DRAW)
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48+
vertexShaderStr :=
49+
`#version 330 core
50+
layout (location = 0) in vec3 aPos;
51+
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void main()
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{
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gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
55+
}`
56+
vertexShader := gl.CreateShader(gl.VERTEX_SHADER)
57+
csources, free := gl.Strs(vertexShaderStr)
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gl.ShaderSource(vertexShader, 1, csources, nil)
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free()
60+
gl.CompileShader(vertexShader)
61+
var status int32
62+
gl.GetShaderiv(vertexShader, gl.COMPILE_STATUS, &status)
63+
if status == gl.FALSE {
64+
var logLength int32
65+
gl.GetShaderiv(vertexShader, gl.INFO_LOG_LENGTH, &logLength)
66+
log := strings.Repeat("\x00", int(logLength+1))
67+
gl.GetShaderInfoLog(vertexShader, logLength, nil, gl.Str(log))
68+
panic("failed to compile vertex shader \n" + log)
69+
}
70+
71+
fragmentShaderStr := `
72+
#version 330 core
73+
out vec4 FragColor;
74+
75+
void main()
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{
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FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);
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} `
79+
80+
fragmentShader := gl.CreateShader(gl.VERTEX_SHADER)
81+
csources, free = gl.Strs(fragmentShaderStr)
82+
gl.ShaderSource(fragmentShader, 1, csources, nil)
83+
free()
84+
gl.CompileShader(fragmentShader)
85+
86+
gl.GetShaderiv(fragmentShader, gl.COMPILE_STATUS, &status)
87+
if status == gl.FALSE {
88+
var logLength int32
89+
gl.GetShaderiv(fragmentShader, gl.INFO_LOG_LENGTH, &logLength)
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log := strings.Repeat("\x00", int(logLength+1))
91+
gl.GetShaderInfoLog(fragmentShader, logLength, nil, gl.Str(log))
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panic("failed to compile vertex shader \n" + log)
93+
}
94+
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for {
96+
for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
97+
switch event.(type) {
98+
case *sdl.QuitEvent:
99+
return
100+
}
101+
}
102+
}
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104+
}

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