Initial

shaders/vertex.glsl

@@ -0,0 +1,25 @@
+#version 130
+in vec3 aPos;
+in vec2 aTexCoord;
+out vec2 texcoord;
+
+uniform vec2 cameraPos;
+uniform float cameraScale;
+uniform vec2 windowSize;
+uniform vec2 screenshotSize;
+uniform vec2 cursorPos;
+
+vec3 to_world(vec3 v) {
+    vec2 ratio = vec2(
+        windowSize.x / screenshotSize.x / cameraScale,
+        windowSize.y / screenshotSize.y / cameraScale);
+    return vec3((v.x / screenshotSize.x * 2.0 - 1.0) / ratio.x,
+                (v.y / screenshotSize.y * 2.0 - 1.0) / ratio.y,
+                v.z);
+}
+
+void main()
+{
+  gl_Position = vec4(to_world((aPos - vec3(cameraPos * vec2(1.0, -1.0), 0.0))), 1.0);
+  texcoord = aTexCoord;
+}