From 08bcf7f42534a61d29c96a44e19e15611ed6e4f8 Mon Sep 17 00:00:00 2001
From: Jelle Licht <jlicht@fsfe.org>
Date: Tue, 6 Oct 2020 13:50:25 +0200
Subject: graphics: Improve GLSL 1.2 compatibility.

---
 chickadee/graphics/particles.scm |  8 ++++----
 chickadee/graphics/phong.scm     |  4 ++--
 chickadee/graphics/shapes.scm    | 29 ++++++++++++++++++++++++++++-
 chickadee/graphics/sprite.scm    | 12 ++++++------
 4 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/chickadee/graphics/particles.scm b/chickadee/graphics/particles.scm
index 0cd275e..90cfa11 100644
--- a/chickadee/graphics/particles.scm
+++ b/chickadee/graphics/particles.scm
@@ -148,7 +148,7 @@ void main(void) {
     t = life / lifetime;
     int numTiles = animationRows * animationColumns;
     int tile = int(numTiles * (1.0 - t));
-    float tx = float(tile % animationColumns) / animationColumns;
+    float tx = float(mod(tile, animationColumns)) / animationColumns;
     float ty = float(tile / animationColumns) / animationRows;
     float tw = 1.0 / animationColumns;
     float th = 1.0 / animationRows;
@@ -158,8 +158,8 @@ void main(void) {
 "
    "
 #ifdef GLSL120
-attribute vec2 fragTex;
-attribute float t;
+varying vec2 fragTex;
+varying float t;
 #else
 in vec2 fragTex;
 in float t;
@@ -174,7 +174,7 @@ uniform vec4 endColor;
 void main (void) {
 #ifdef GLSL330
     fragColor = mix(endColor, startColor, t) * texture(color_texture, fragTex);
-#elif ifdef GLSL130
+#elif defined(GLSL130)
     gl_FragColor = mix(endColor, startColor, t) * texture2D(color_texture, fragTex);
 #endif
 }
diff --git a/chickadee/graphics/phong.scm b/chickadee/graphics/phong.scm
index ab34fce..514bb24 100644
--- a/chickadee/graphics/phong.scm
+++ b/chickadee/graphics/phong.scm
@@ -171,8 +171,8 @@ struct DirectionalLight {
 };
 
 #ifdef GLSL120
-attribute vec3 fragNorm;
-attribute vec2 fragTex;
+varying vec3 fragNorm;
+varying vec2 fragTex;
 #else
 in vec3 fragNorm;
 in vec2 fragTex;
diff --git a/chickadee/graphics/shapes.scm b/chickadee/graphics/shapes.scm
index 79a73b6..e5d985c 100644
--- a/chickadee/graphics/shapes.scm
+++ b/chickadee/graphics/shapes.scm
@@ -165,7 +165,7 @@ void main(void) {
 "
               "
 #ifdef GLSL120
-attribute vec2 fragTex;
+varying vec2 fragTex;
 #else
 in vec2 fragTex;
 #endif
@@ -196,6 +196,32 @@ void main (void) {
     }
     dy = abs(v);
 
+#ifdef GLSL120
+    // none
+    if (cap == 0) {
+      d = infinity;
+    }
+    // butt
+    else if (cap == 1) {
+      d = max(dx + w / 2 - 2 * r, dy);
+    }
+    // square
+    else if (cap ==  2) {
+      d = max(dx, dy);
+    }
+    // round
+    else if (cap == 3) {
+      d = sqrt(dx * dx + dy * dy);
+    }
+    // triangle out
+    else if (cap == 4) {
+      d = dx + dy;
+    }
+    // triangle in
+    else if (cap == 5) {
+      d = max(dy, w / 2 - r + dx - dy);
+    }
+#else
     switch (cap) {
     // none
     case 0:
@@ -222,6 +248,7 @@ void main (void) {
       d = max(dy, w / 2 - r + dx - dy);
       break;
     }
+#endif
   } else {
     d = abs(v);
   }
diff --git a/chickadee/graphics/sprite.scm b/chickadee/graphics/sprite.scm
index 4a78292..5fc3203 100644
--- a/chickadee/graphics/sprite.scm
+++ b/chickadee/graphics/sprite.scm
@@ -52,10 +52,10 @@
 #ifdef GLSL330
 layout (location = 0) in vec2 position;
 layout (location = 1) in vec2 tex;
-#elif ifdef GLSL130
+#elif defined(GLSL130)
 in vec2 position;
 in vec2 tex;
-#elif ifdef GLSL120
+#elif defined(GLSL120)
 attribute vec2 position;
 attribute vec2 tex;
 #endif
@@ -74,7 +74,7 @@ void main(void) {
      "
 
 #ifdef GLSL120
-attribute vec2 fragTex;
+varying vec2 fragTex;
 #else
 in vec2 fragTex;
 #endif
@@ -415,7 +415,7 @@ attribute vec4 tint;
 #endif
 #ifdef GLSL120
 varying vec2 fragTex;
-varying vec2 fragTint;
+varying vec4 fragTint;
 #else
 out vec2 fragTex;
 out vec4 fragTint;
@@ -430,8 +430,8 @@ void main(void) {
 "
      "
 #ifdef GLSL120
-attribute vec2 fragTex;
-attribute vec4 fragTint;
+varying vec2 fragTex;
+varying vec4 fragTint;
 #else
 in vec2 fragTex;
 in vec4 fragTint;
-- 
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