GL3 Test: Use instancing

2 files changed, 26 insertions, 11 deletions

diff --git a/shaders/rect.frag b/shaders/rect.frag
index c5dedf9..5e3af9d 100644
--- a/shaders/rect.frag
+++ b/shaders/rect.frag
@@ -10,10 +10,9 @@
    specified precisely in pixels to draw sharp lines.  The border width is just
    hardcoded, but could be made a uniform or vertex attribute easily enough. */
 
-uniform vec2 u_size;
-uniform vec4 u_fillColor;
-
 noperspective in vec2 f_uv;
+noperspective in vec2 f_size;
+noperspective in vec4 f_fillColor;
 
 layout(location = 0) out vec4 FragColor;
 
@@ -22,14 +21,14 @@ main()
 {
 	const float borderWidth = 2.0;
 
-	vec4  borderColor = u_fillColor + vec4(0.0, 0.4, 0.4, 0.0);
+	vec4  borderColor = f_fillColor + vec4(0.0, 0.4, 0.4, 0.0);
 	float t           = step(borderWidth, f_uv[1]);
-	float r           = step(borderWidth, u_size.x - f_uv[0]);
-	float b           = step(borderWidth, u_size.y - f_uv[1]);
+	float r           = step(borderWidth, f_size.x - f_uv[0]);
+	float b           = step(borderWidth, f_size.y - f_uv[1]);
 	float l           = step(borderWidth, f_uv[0]);
 	float fillMix     = t * r * b * l;
 	float borderMix   = 1.0 - fillMix;
-	vec4  fill        = fillMix * u_fillColor;
+	vec4  fill        = fillMix * f_fillColor;
 	vec4  border      = borderMix * borderColor;
 
 	FragColor = fill + border;
diff --git a/shaders/rect.vert b/shaders/rect.vert
index de74fa7..bf2e951 100644
--- a/shaders/rect.vert
+++ b/shaders/rect.vert
@@ -3,16 +3,32 @@
 /* The vertex shader is trivial, but forwards scaled UV coordinates (in pixels)
    to the fragment shader for drawing the border. */
 
-uniform mat4 MVP;
-uniform vec2 u_size;
+uniform mat4 u_projection;
 
-in vec2 v_position;
+layout(location = 0) in vec2 v_position;
+layout(location = 1) in vec2 v_origin;
+layout(location = 2) in vec2 v_size;
+layout(location = 3) in vec4 v_fillColor;
 
 noperspective out vec2 f_uv;
+noperspective out vec2 f_size;
+noperspective out vec4 f_fillColor;
 
 void
 main()
 {
-	f_uv        = v_position * u_size;
+	// clang-format off
+	mat4 m = mat4(v_size[0],   0.0,         0.0, 0.0,
+	              0.0,         v_size[1],   0.0, 0.0,
+	              0.0,         0.0,         1.0, 0.0,
+	              v_origin[0], v_origin[1], 0.0, 1.0);
+	// clang-format on
+
+	mat4 MVP = u_projection * m;
+
+	f_uv        = v_position * v_size;
+	f_size      = v_size;
+	f_fillColor = v_fillColor;
+
 	gl_Position = MVP * vec4(v_position, 0.0, 1.0);
 }