First successful homogenous Transformation on GPU

1 files changed, 15 insertions, 1 deletions

diff --git a/graphics.go b/graphics.go
index 91edcce..a5c7373 100644
--- a/graphics.go
+++ b/graphics.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 
 	"github.com/go-gl/gl/v4.6-core/gl"
+	"github.com/go-gl/mathgl/mgl32"
 )
 
 var (
@@ -23,9 +24,13 @@ const (
 	// vertex shader to draw points
 	VERTEX_SHADER = `
         #version 410
+
+		uniform mat4 trafo;
+
         in vec3 vp;
+
         void main() {
-            gl_Position = vec4(vp, 1.0);
+            gl_Position = trafo * vec4(vp, 1.0);
         }
     ` + "\x00"
 
@@ -45,6 +50,8 @@ type Graphics struct {
 	vertexShader uint32
 	fragmentShader uint32
 	program uint32
+	trafo mgl32.Mat4
+	trafoUniform int32
 }
 
 func newGraphics() Graphics {
@@ -79,6 +86,11 @@ func newGraphics() Graphics {
 	// create VAO
 	graphics.vao = makeVao(triangle)
 
+	// create transformation matrix
+	graphics.trafo = mgl32.HomogRotate3D(float32(1.57), mgl32.Vec3{0, 1, 1})  // mgl32.Ident4()
+	graphics.trafoUniform = gl.GetUniformLocation(graphics.program, gl.Str("trafo\x00"))
+	gl.UniformMatrix4fv(graphics.trafoUniform, 1, false, &graphics.trafo[0])
+
 	return graphics
 }
 
@@ -86,6 +98,8 @@ func (graphics Graphics) draw() {
 	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
 	gl.UseProgram(graphics.program)
 
+	gl.UniformMatrix4fv(graphics.trafoUniform, 1, false, &graphics.trafo[0])
+
 	gl.BindVertexArray(graphics.vao)
 	gl.DrawArrays(gl.TRIANGLES, 0, int32(len(triangle)/3))
 }