From 0491a71da197e862b849c1c93c4fb59e463118d1 Mon Sep 17 00:00:00 2001
From: justin <justin.g.kruger@gmail.com>
Date: Thu, 20 Nov 2025 12:34:36 +0000
Subject: [PATCH] Improve window drawing

---
 shader/pull/window.frag |  1 -
 shader/pull/window.vert | 14 +++++++++-----
 src/Dodge/Render.hs     |  3 ++-
 3 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/shader/pull/window.frag b/shader/pull/window.frag
index 41a9e5ff7..b112743c2 100644
--- a/shader/pull/window.frag
+++ b/shader/pull/window.frag
@@ -10,5 +10,4 @@ void main()
   float cloudz = texture(cloudpos, vScreenPos).z;
   fColOverCloud = ( cloudz > vPos.z ? vec4(0) : vCol);
   fColUnderCloud = ( cloudz > vPos.z ? vCol : vec4(0));
-  fColUnderCloud = vec4(0);
 }
diff --git a/shader/pull/window.vert b/shader/pull/window.vert
index 1ad2a79e0..bfad01a30 100644
--- a/shader/pull/window.vert
+++ b/shader/pull/window.vert
@@ -5,18 +5,22 @@ layout (std430, binding = 1) readonly buffer Pos { PosCol data[]; };
 out vec4 vCol;
 out vec4 vPos;
 out vec2 vScreenPos;
-//int indices[6] = {0,1,3,0,3,2};
 int indices[6] = 
     {0,3,1
     ,0,2,3};
 // note reversed compared to walls
 void main()
 {
-    vCol = data[gl_VertexID / 6].col;
-    vec4 pp = data[gl_VertexID / 6].pospos;
+    vCol = data[gl_VertexID / 12].col;
+    vec4 pp = data[gl_VertexID / 12].pospos;
     int j = indices[gl_VertexID % 6];
-    //float z = (j > 1.5 ? 5000 : 0);
-    float z = (j > 1.5 ? 200 : 0);
+    bool t = gl_VertexID % 12 > 5.5;
+    float z = (j > 1.5 
+            ? (t ? 100 : 5000)
+            : (t ?   0 :  100)
+            );
+    // we draw two quads: one which can be below clouds,
+    // and one which is always above
     vec2 xy = (j % 2 > 0 ? pp.xy : pp.zw);
     vPos = vec4( xy, z, 1);
     gl_Position = theMat * vPos;
diff --git a/src/Dodge/Render.hs b/src/Dodge/Render.hs
index 840dbac8f..e6e6087f4 100644
--- a/src/Dodge/Render.hs
+++ b/src/Dodge/Render.hs
@@ -310,10 +310,11 @@ doDrawing' win pdata u = do
     glEnable GL_BLEND
     --glBlendFunc GL_SRC_ALPHA GL_ONE
     glBindTextureUnit 3 (pdata ^. fboPos . _2 . unTO)
+    -- with all source alphas 0.25, alpha -> 0.5
     glBlendFunc GL_ONE_MINUS_DST_ALPHA GL_ONE_MINUS_SRC_ALPHA
     glUseProgram $ pdata ^. windowPullShader
     glBindVertexArray $ pdata ^. dummyVAO
-    glDrawArrays GL_TRIANGLES 0 (fromIntegral nWins * 6)
+    glDrawArrays GL_TRIANGLES 0 (fromIntegral nWins * 12)
     glDisable GL_DEPTH_CLAMP
     glDisable GL_CULL_FACE
     glInvalidateBufferData (pdata ^. vboShapes . vboName)