tofu

commit 08820a0fe9c3eebac8fff31cbbbf55b4cdeaa958
parent fc6eaa5e3954f98dbe2255dbce581d24a3371d74
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Thu, 17 Oct 2024 21:38:59 +0900

link shaders

Diffstat:
M
cmd/sample/main.go
 | 
83
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 83 insertions(+), 0 deletions(-)
diff --git a/cmd/sample/main.go b/cmd/sample/main.go
@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"math"
 	"runtime"
+	"strings"
 
 	"github.com/go-gl/gl/v3.3-core/gl"
 	"github.com/go-gl/glfw/v3.3/glfw"
@@ -30,6 +32,65 @@ func processInput(w *glfw.Window) {
 	}
 }
 
+func newShader(src string, xtype uint32) (shader uint32, err error) {
+	shader = gl.CreateShader(xtype)
+	cstrs, free := gl.Strs(src + "\x00")
+	defer free()
+	gl.ShaderSource(shader, 1, cstrs, nil)
+	gl.CompileShader(shader)
+
+	var success int32
+	gl.GetShaderiv(shader, gl.COMPILE_STATUS, &success)
+	if success == gl.FALSE {
+		var logLength int32
+		gl.GetShaderiv(shader, gl.INFO_LOG_LENGTH, &logLength)
+		l := gl.Str(strings.Repeat("\x00", int(logLength)))
+		gl.GetShaderInfoLog(shader, logLength, nil, l)
+		gl.DeleteShader(shader)
+		return 0, fmt.Errorf("%v", gl.GoStr(l))
+	}
+	return shader, nil
+}
+
+func linkShaders(vertexShader, fragmentShader uint32) (shader uint32, err error) {
+	shader = gl.CreateProgram()
+	gl.AttachShader(shader, vertexShader)
+	gl.AttachShader(shader, fragmentShader)
+	gl.LinkProgram(shader)
+
+	var success int32
+	gl.GetProgramiv(shader, gl.LINK_STATUS, &success)
+	if success == gl.FALSE {
+		var logLength int32
+		gl.GetProgramiv(shader, gl.INFO_LOG_LENGTH, &logLength)
+		l := gl.Str(strings.Repeat("\x00", int(logLength)))
+		gl.GetProgramInfoLog(shader, logLength, nil, l)
+		return 0, fmt.Errorf("%v", gl.GoStr(l))
+	}
+	return shader, nil
+}
+
+var vertices = []float32{
+	-0.5, -0.5, 0.0,
+	0.5, -0.5, 0.0,
+	0.0, 0.5, 0.0,
+}
+
+const vertexShaderSource = `#version 330 core
+layout (location = 0) in vec3 aPos;
+void main() {
+	gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+}
+`
+
+const fragmentShaderSource = `#version 330 core
+out vec4 FragColor;
+
+void main() {
+	FragColor = vec4(1.0, 0.5, 0.2, 1.0);
+}
+`
+
 func main() {
 	err := glfw.Init()
 	if err != nil {
@@ -50,8 +111,30 @@ func main() {
 	}
 	gl.Viewport(0, 0, winW, winH)
 
+	vertexShader, err := newShader(vertexShaderSource, gl.VERTEX_SHADER)
+	if err != nil {
+		log.Fatalf("crete vertex shader: %v", err)
+	}
+	fragmentShader, err := newShader(fragmentShaderSource, gl.FRAGMENT_SHADER)
+	if err != nil {
+		log.Fatalf("crete fragment shader: %v", err)
+	}
+	shaderProgram, err := linkShaders(vertexShader, fragmentShader)
+	if err != nil {
+		log.Fatalf("link shaders: %v", err)
+	}
+	gl.UseProgram(shaderProgram)
+	gl.DeleteShader(vertexShader)
+	gl.DeleteShader(fragmentShader)
+
 	window.SetFramebufferSizeCallback(framebufferSizeCallback)
 
+	var VBO uint32
+	gl.GenBuffers(1, &VBO)
+	gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
+	gl.BufferData(gl.ARRAY_BUFFER, len(vertices) * 4,
+		gl.Ptr(vertices), gl.STATIC_DRAW)
+
 	for !window.ShouldClose() {
 		processInput(window)
 		gl.ClearColor(0.2, 0.3, 0.3, 1.0)