opengl lights

Author: jackmott

gogl/camera.go

@@ -0,0 +1,94 @@
+package gogl
+
+import (
+	"github.com/go-gl/mathgl/mgl32"
+	"math"
+)
+
+type Direction int
+
+const (
+	Forward Direction = iota
+	Backward
+	Left
+	Right
+	Nowhere
+)
+
+type Camera struct {
+	Position mgl32.Vec3
+	Front    mgl32.Vec3
+	Up       mgl32.Vec3
+	Right    mgl32.Vec3
+
+	WorldUp mgl32.Vec3
+
+	Yaw           float32
+	Pitch         float32
+	MovementSpeed float32
+	MouseSens     float32
+	Zoom          float32
+}
+
+func NewCamera(position mgl32.Vec3, worldUp mgl32.Vec3, yaw, pitch, speed, sens float32) *Camera {
+	camera := Camera{}
+	camera.Position = position
+	camera.WorldUp = worldUp
+	camera.Yaw = yaw
+	camera.Pitch = pitch
+	camera.MovementSpeed = speed
+	camera.MouseSens = sens
+	camera.updateVectors()
+	return &camera
+
+}
+
+func (camera *Camera) UpdateCamera(direction Direction, deltaT, xoffset, yoffset float32) {
+	magnitude := camera.MovementSpeed * deltaT
+	//fmt.Println("mag:", magnitude)
+	switch direction {
+	case Forward:
+		camera.Position = camera.Position.Add(camera.Front.Mul(magnitude))
+	case Backward:
+		camera.Position = camera.Position.Sub(camera.Front.Mul(magnitude))
+	case Left:
+		camera.Position = camera.Position.Sub(camera.Right.Mul(magnitude))
+	case Right:
+		camera.Position = camera.Position.Add(camera.Right.Mul(magnitude))
+	case Nowhere:
+	}
+
+	xoffset *= camera.MouseSens
+	yoffset *= camera.MouseSens
+
+	camera.Yaw += xoffset
+	camera.Pitch -= yoffset
+
+	if camera.Pitch > 90.0 {
+		camera.Pitch = 90
+	}
+	if camera.Pitch < -90.0 {
+		camera.Pitch = -90
+	}
+
+	//fmt.Println("xoffset:", xoffset, "yoffset:", yoffset, "yaw:", camera.Yaw, "pitch:", camera.Pitch)
+
+	camera.updateVectors()
+
+}
+
+func (camera *Camera) GetViewMatrix() mgl32.Mat4 {
+	center := camera.Position.Add(camera.Front)
+	return mgl32.LookAt(camera.Position.X(), camera.Position.Y(), camera.Position.Z(), center.X(), center.Y(), center.Z(), camera.Up.X(), camera.Up.Y(), camera.Up.Z())
+}
+
+func (camera *Camera) updateVectors() {
+	front := mgl32.Vec3{float32(math.Cos(float64(mgl32.DegToRad(camera.Yaw))) * math.Cos(float64(mgl32.DegToRad(camera.Pitch)))),
+		float32(math.Sin(float64(mgl32.DegToRad(camera.Pitch)))),
+		float32(math.Sin(float64(mgl32.DegToRad(camera.Yaw))) * math.Cos(float64(mgl32.DegToRad(camera.Pitch))))}
+
+	camera.Front = front.Normalize()
+	camera.Right = camera.Front.Cross(camera.WorldUp).Normalize()
+	camera.Up = camera.Right.Cross(camera.Front).Normalize()
+
+}

gogl/gogl.go

@@ -182,3 +182,9 @@ func UnbindVertexArray() {
 func UseProgram(programID ProgramID) {
 	gl.UseProgram(uint32(programID))
 }
+
+func TriangleNormal(p1, p2, p3 mgl32.Vec3) mgl32.Vec3 {
+	U := p2.Sub(p1)
+	V := p3.Sub(p1)
+	return U.Cross(V).Normalize()
+}

gogl/shader.go

@@ -50,6 +50,13 @@ func (shader *Shader) SetMat4(name string, mat mgl32.Mat4) {
 	gl.UniformMatrix4fv(location, 1, false, &m4[0])
 }
 
+func (shader *Shader) SetVec3(name string, v mgl32.Vec3) {
+	name_cstr := gl.Str(name + "\x00")
+	location := gl.GetUniformLocation(uint32(shader.id), name_cstr)
+	v3 := [3]float32(v)
+	gl.Uniform3fv(location, 1, &v3[0])
+}
+
 func getModifiedTime(filePath string) (time.Time, error) {
 
 	file, err := os.Stat(filePath)

hellotriangle/hellotriangle.go

@@ -1,7 +1,3 @@
-// Make shader hotloading fail gracefully and retry
-// Make an attribpointer helper function
-// Make a texture
-
 package main
 
 import (
@@ -13,7 +9,7 @@ import (
 	"time"
 )
 
-const winWidth = 1280
+const winWidth = 720
 const winHeight = 720
 
 func main() {
@@ -91,19 +87,45 @@ func main() {
 		-0.5, 0.5, 0.5, 0.0, 0.0,
 		-0.5, 0.5, -0.5, 0.0, 1.0}
 
+	normals := make([]float32, 36*3)
+	for tri := 0; tri < 12; tri++ {
+		index := tri * 15
+		p1 := mgl32.Vec3{vertices[index], vertices[index+1], vertices[index+2]}
+		index += 5
+		p2 := mgl32.Vec3{vertices[index], vertices[index+1], vertices[index+2]}
+		index += 5
+		p3 := mgl32.Vec3{vertices[index], vertices[index+1], vertices[index+2]}
+		normal := gogl.TriangleNormal(p1, p2, p3)
+		normals[tri*9] = normal.X()
+		normals[tri*9+1] = normal.Y()
+		normals[tri*9+2] = normal.Z()
+
+		normals[tri*9+3] = normal.X()
+		normals[tri*9+4] = normal.Y()
+		normals[tri*9+5] = normal.Z()
+
+		normals[tri*9+6] = normal.X()
+		normals[tri*9+7] = normal.Y()
+		normals[tri*9+8] = normal.Z()
+
+	}
+
 	cubePositions := []mgl32.Vec3{
 		mgl32.Vec3{0.0, 0.0, 0.0},
 		mgl32.Vec3{2.0, 5.0, -10.0},
 		mgl32.Vec3{1.0, -5.0, 1.0}}
 
-	gogl.GenBindBuffer(gl.ARRAY_BUFFER)
 	VAO := gogl.GenBindVertexArray()
+	gogl.GenBindBuffer(gl.ARRAY_BUFFER)
 	gogl.BufferDataFloat(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW)
-
 	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 5*4, nil)
 	gl.EnableVertexAttribArray(0)
 	gl.VertexAttribPointer(1, 2, gl.FLOAT, false, 5*4, gl.PtrOffset(3*4))
 	gl.EnableVertexAttribArray(1)
+	gogl.GenBindBuffer(gl.ARRAY_BUFFER)
+	gogl.BufferDataFloat(gl.ARRAY_BUFFER, normals, gl.STATIC_DRAW)
+	gl.VertexAttribPointer(2, 3, gl.FLOAT, false, 3*4, nil)
+	gl.EnableVertexAttribArray(2)
 	gogl.UnbindVertexArray()
 
 	keyboardState := sdl.GetKeyboardState()
@@ -149,6 +171,8 @@ func main() {
 		viewMatrix := camera.GetViewMatrix()
 		shaderProgram.SetMat4("projection", projectionMatrix)
 		shaderProgram.SetMat4("view", viewMatrix)
+		shaderProgram.SetVec3("lightPos", mgl32.Vec3{2.0, 5.0, 5.0})
+		shaderProgram.SetVec3("lightColor", mgl32.Vec3{1.0, 0.0, 0.0})
 		gogl.BindTexture(texture)
 		gogl.BindVertexArray(VAO)
 		for i, pos := range cubePositions {

hellotriangle/shaders/hello.vert

@@ -1,15 +1,21 @@
 #version 330 core
 layout (location = 0) in vec3 aPos;
 layout (location = 1) in vec2 aTexCoord;
+layout (location = 2) in vec3 aNormal;
 
 out vec2 TexCoord;
 
+out vec3 FragPos;
+out vec3 Normal;
+
 uniform mat4 model;
 uniform mat4 view;
 uniform mat4 projection;
 
 void main() 
 {
-    gl_Position = projection * view * model * vec4(aPos,1.0f);
+    Normal = aNormal;
+    FragPos = vec3(model * vec4(aPos,1.0));
+    gl_Position = projection * view * vec4(FragPos,1.0f);
     TexCoord = vec2(aTexCoord.x,1.0 - aTexCoord.y);
 }

hellotriangle/shaders/quadtexture.frag

@@ -1,9 +1,24 @@
 #version 330 core
 out vec4 FragColor;
+
+
 in vec2 TexCoord;
+in vec3 Normal;
+in vec3 FragPos;
+
+
 
 uniform sampler2D texture1;
+uniform vec3 lightPos;
+uniform vec3 lightColor; //color/brightness
+
 
 void main() {
-    FragColor = texture(texture1,TexCoord);    
+        
+    // diffuse
+    vec3 lightDir = normalize(lightPos - FragPos);
+    float diff = max(dot(Normal,lightDir),0.0);
+    vec3 diffuse = diff * lightColor;
+    vec3 ambient = lightColor * 0.3;
+    FragColor = vec4(ambient + diffuse,1.0) * texture(texture1,TexCoord);    
 }