graphics: Cache values for uniformMatrix4fv

internal/graphics/program.go

@@ -116,7 +116,24 @@ func initialize(c *opengl.Context) error {
 	return nil
 }
 
-var lastProgram opengl.Program
+func areSameFloat32Array(a, b []float32) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := 0; i < len(a); i++ {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+var (
+	lastProgram          opengl.Program
+	lastProjectionMatrix []float32
+	lastModelviewMatrix  []float32
+	lastColorMatrix      []float32
+)
 
 type programFinisher func()
 
@@ -128,12 +145,21 @@ func useProgramForTexture(c *opengl.Context, projectionMatrix []float32, texture
 	if !lastProgram.Equals(programTexture) {
 		c.UseProgram(programTexture)
 		lastProgram = programTexture
+		lastProjectionMatrix = nil
+		lastModelviewMatrix = nil
+		lastColorMatrix = nil
 	}
 	program := programTexture
 
 	c.BindElementArrayBuffer(indexBufferQuads)
 
-	c.UniformFloats(program, "projection_matrix", projectionMatrix)
+	if !areSameFloat32Array(lastProjectionMatrix, projectionMatrix) {
+		c.UniformFloats(program, "projection_matrix", projectionMatrix)
+		if lastProjectionMatrix == nil {
+			lastProjectionMatrix = make([]float32, 16)
+		}
+		copy(lastProjectionMatrix, projectionMatrix)
+	}
 
 	ma := float32(geo.Element(0, 0))
 	mb := float32(geo.Element(0, 1))
@@ -141,13 +167,20 @@ func useProgramForTexture(c *opengl.Context, projectionMatrix []float32, texture
 	md := float32(geo.Element(1, 1))
 	tx := float32(geo.Element(0, 2))
 	ty := float32(geo.Element(1, 2))
-	glModelviewMatrix := []float32{
+	modelviewMatrix := []float32{
 		ma, mc, 0, 0,
 		mb, md, 0, 0,
 		0, 0, 1, 0,
 		tx, ty, 0, 1,
 	}
-	c.UniformFloats(program, "modelview_matrix", glModelviewMatrix)
+	if !areSameFloat32Array(lastModelviewMatrix, modelviewMatrix) {
+		c.UniformFloats(program, "modelview_matrix", modelviewMatrix)
+		if lastModelviewMatrix == nil {
+			lastModelviewMatrix = make([]float32, 16)
+		}
+		copy(lastModelviewMatrix, modelviewMatrix)
+	}
+
 	c.UniformInt(program, "texture", 0)
 
 	e := [4][5]float32{}
@@ -157,17 +190,23 @@ func useProgramForTexture(c *opengl.Context, projectionMatrix []float32, texture
 		}
 	}
 
-	glColorMatrix := []float32{
+	colorMatrix := []float32{
 		e[0][0], e[1][0], e[2][0], e[3][0],
 		e[0][1], e[1][1], e[2][1], e[3][1],
 		e[0][2], e[1][2], e[2][2], e[3][2],
 		e[0][3], e[1][3], e[2][3], e[3][3],
 	}
-	c.UniformFloats(program, "color_matrix", glColorMatrix)
-	glColorMatrixTranslation := []float32{
+	if !areSameFloat32Array(lastColorMatrix, colorMatrix) {
+		c.UniformFloats(program, "color_matrix", colorMatrix)
+		if lastColorMatrix == nil {
+			lastColorMatrix = make([]float32, 16)
+		}
+		copy(lastColorMatrix, colorMatrix)
+	}
+	colorMatrixTranslation := []float32{
 		e[0][4], e[1][4], e[2][4], e[3][4],
 	}
-	c.UniformFloats(program, "color_matrix_translation", glColorMatrixTranslation)
+	c.UniformFloats(program, "color_matrix_translation", colorMatrixTranslation)
 
 	// We don't have to call gl.ActiveTexture here: GL_TEXTURE0 is the default active texture
 	// See also: https://www.opengl.org/sdk/docs/man2/xhtml/glActiveTexture.xml