Rearrangement and refactoring and optimizations and more accuracy

1 files changed, 36 insertions, 0 deletions

diff --git a/shaders/gl_upscale_warp_fragment.glsl b/shaders/gl_upscale_warp_fragment.glsl
new file mode 100644
index 0000000..26f0202
--- /dev/null
+++ b/shaders/gl_upscale_warp_fragment.glsl
@@ -0,0 +1,36 @@
+out vec4 outcolor;
+in vec2 frag_texture_coord;
+
+uniform sampler2D source;
+uniform vec2 resolution;
+uniform vec2 src_image_size;
+
+void main() {
+	// Match CRT shader coordinate system exactly
+	vec2 half_pixel = 0.5 / src_image_size;
+	vec2 fragCoord = vec2(frag_texture_coord.x, 1.0 - frag_texture_coord.y) + half_pixel;
+
+	// Convert to pixel coordinates and add pixel centering offset
+	vec2 ipos = fragCoord * resolution + vec2(0.5);
+
+	// Convert to normalized device coordinates [-1, 1]
+	vec2 pos = ipos * (2.0 / resolution) - vec2(1.0);
+
+	// Apply barrel distortion (match CRT warp)
+	vec2 warp = vec2(1.0 / 24.0, 1.0 / 16.0);
+	pos *= vec2(
+		1.0 + (pos.y * pos.y) * warp.x,
+		1.0 + (pos.x * pos.x) * warp.y
+	);
+
+	// Convert back to UV coordinates
+	vec2 uv = (pos + vec2(1.0)) * 0.5;
+
+	// Sample from source with boundary check
+	if (uv.x < 0.0 || uv.x > 1.0 || uv.y < 0.0 || uv.y > 1.0) {
+		outcolor = vec4(0.0, 0.0, 0.0, 1.0);
+	} else {
+		// Sample directly (Y-flip already applied at line 11)
+		outcolor = texture(source, uv, -16.0);
+	}
+}