forked from go-gl/example
/
legacy_cube.go
209 lines (177 loc) · 4.3 KB
/
legacy_cube.go
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// Copyright 2014 The go-gl Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Command legacy-cube demonstrates simple Glow binding usage with the legacy
// OpenGL 2.1 API.
package main
import (
"fmt"
glfw "github.com/go-gl/glfw3"
"github.com/go-gl/glow/gl/2.1/gl"
"image"
"image/draw"
_ "image/png"
"os"
"runtime"
)
var (
texture uint32
rotationX float32
rotationY float32
)
func glfwErrorCallback(err glfw.ErrorCode, desc string) {
fmt.Printf("GLFW error %v: %v\n", err, desc)
}
func init() {
// GLFW event handling must run on the main OS thread
runtime.LockOSThread()
}
func main() {
glfw.SetErrorCallback(glfwErrorCallback)
if !glfw.Init() {
panic("failed to initialize glfw")
}
defer glfw.Terminate()
glfw.WindowHint(glfw.Resizable, glfw.False)
glfw.WindowHint(glfw.ContextVersionMajor, 2)
glfw.WindowHint(glfw.ContextVersionMinor, 1)
window, err := glfw.CreateWindow(800, 600, "Cube", nil, nil)
if err != nil {
panic(err)
}
window.MakeContextCurrent()
if err := gl.Init(); err != nil {
panic(err)
}
texture = newTexture("square.png")
defer gl.DeleteTextures(1, &texture)
setupScene()
for !window.ShouldClose() {
drawScene()
window.SwapBuffers()
glfw.PollEvents()
}
}
func newTexture(file string) uint32 {
imgFile, err := os.Open(file)
if err != nil {
panic(err)
}
img, _, err := image.Decode(imgFile)
if err != nil {
panic(err)
}
rgba := image.NewRGBA(img.Bounds())
if rgba.Stride != rgba.Rect.Size().X*4 {
panic("unsupported stride")
}
draw.Draw(rgba, rgba.Bounds(), img, image.Point{0, 0}, draw.Src)
var texture uint32
gl.Enable(gl.TEXTURE_2D)
gl.GenTextures(1, &texture)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
gl.TexImage2D(
gl.TEXTURE_2D,
0,
gl.RGBA,
int32(rgba.Rect.Size().X),
int32(rgba.Rect.Size().Y),
0,
gl.RGBA,
gl.UNSIGNED_BYTE,
gl.Ptr(rgba.Pix))
return texture
}
func setupScene() {
gl.Enable(gl.DEPTH_TEST)
gl.Enable(gl.LIGHTING)
gl.ClearColor(0.5, 0.5, 0.5, 0.0)
gl.ClearDepth(1)
gl.DepthFunc(gl.LEQUAL)
ambient := []float32{0.5, 0.5, 0.5, 1}
diffuse := []float32{1, 1, 1, 1}
lightPosition := []float32{-5, 5, 10, 0}
gl.Lightfv(gl.LIGHT0, gl.AMBIENT, &ambient[0])
gl.Lightfv(gl.LIGHT0, gl.DIFFUSE, &diffuse[0])
gl.Lightfv(gl.LIGHT0, gl.POSITION, &lightPosition[0])
gl.Enable(gl.LIGHT0)
gl.MatrixMode(gl.PROJECTION)
gl.LoadIdentity()
gl.Frustum(-1, 1, -1, 1, 1.0, 10.0)
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
}
func destroyScene() {
}
func drawScene() {
gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
gl.MatrixMode(gl.MODELVIEW)
gl.LoadIdentity()
gl.Translatef(0, 0, -3.0)
gl.Rotatef(rotationX, 1, 0, 0)
gl.Rotatef(rotationY, 0, 1, 0)
rotationX += 0.5
rotationY += 0.5
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.Color4f(1, 1, 1, 1)
gl.Begin(gl.QUADS)
gl.Normal3f(0, 0, 1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, -1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, -1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, 1)
gl.Normal3f(0, 0, -1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, 1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, 1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, -1)
gl.Normal3f(0, 1, 0)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, 1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, -1)
gl.Normal3f(0, -1, 0)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, -1, -1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, 1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, 1)
gl.Normal3f(1, 0, 0)
gl.TexCoord2f(1, 0)
gl.Vertex3f(1, -1, -1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(1, 1, -1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(1, 1, 1)
gl.TexCoord2f(0, 0)
gl.Vertex3f(1, -1, 1)
gl.Normal3f(-1, 0, 0)
gl.TexCoord2f(0, 0)
gl.Vertex3f(-1, -1, -1)
gl.TexCoord2f(1, 0)
gl.Vertex3f(-1, -1, 1)
gl.TexCoord2f(1, 1)
gl.Vertex3f(-1, 1, 1)
gl.TexCoord2f(0, 1)
gl.Vertex3f(-1, 1, -1)
gl.End()
}