Use GLSL shaders for sprites.

* 2d/sprite.scm: (sprite-vertex): Remove color vertex.
  (r-offset): Delete it.
  (pack-sprite-vertices): Remove logic moved to shader.
  (draw-sprite-vertices): Remove color vertex array rendering.
  (sprite-shader): New variable.
  (<sprite>): Remove dirty field and adjust setters.
  (make-anchor): New procedure.
  (update-sprite-vertices!): Use new 'pack-sprite-vertices'.
  (make-sprite): Use 'make-anchor' and 'update-sprite-vertices!'.
  (dirty-sprite-setter): Delete it.
  (load-sprite): Formatting.
  (sprite-animation-texture): Delete it.
  (drawable-texture): New procedure.
  (sprite-texture): Extract body to 'drawable-texture'.
  (sprite-anchor-vector): Delete it.
  (set-sprite-anchor!): Reimplemented.
  (update-sprite-animator!): Update vertices.
  (draw-sprite): Use shader program.
  (<sprite-batch>, make-sprite-batch, sprite-batch?,
  sprite-batch-max-size, sprite-batch-size, set-sprite-batch-size!,
  sprite-batch-texture, set-sprite-batch-texture!,
  sprite-batch-vertices, sprite-batch-draw, with-sprite-batch): Delete
  all sprite batch code.
* data/Makefile.am (shadersdir, shaders_DATA): New variables.
* data/shaders/sprite-fragment.glsl: New shader.
* data/shaders/sprite-vertex.glsl: New shader.

3 files changed, 39 insertions, 0 deletions

diff --git a/data/Makefile.am b/data/Makefile.am
index 552da87..b6d0d74 100644
--- a/data/Makefile.am
+++ b/data/Makefile.am
@@ -1,2 +1,7 @@
 fontsdir = $(pkgdatadir)/fonts
 fonts_DATA = fonts/DejaVuSans.ttf
+
+shadersdir = $(pkgdatadir)/shaders
+shaders_DATA = 					\
+  shaders/sprite-vertex.glsl			\
+  shaders/sprite-fragment.glsl
diff --git a/data/shaders/sprite-fragment.glsl b/data/shaders/sprite-fragment.glsl
new file mode 100644
index 0000000..3dd10f1
--- /dev/null
+++ b/data/shaders/sprite-fragment.glsl
@@ -0,0 +1,8 @@
+#version 120
+
+uniform sampler2D color_texture;
+uniform vec4 color;
+
+void main (void) {
+    gl_FragColor = texture2D(color_texture, gl_TexCoord[0].st) * color;
+}
diff --git a/data/shaders/sprite-vertex.glsl b/data/shaders/sprite-vertex.glsl
new file mode 100644
index 0000000..d6efd3f
--- /dev/null
+++ b/data/shaders/sprite-vertex.glsl
@@ -0,0 +1,26 @@
+#version 120
+
+uniform mat4 projection;
+uniform vec2 position;
+uniform vec2 anchor;
+uniform vec2 scale;
+uniform float rotation;
+
+void main(void) {
+    mat4 rotationMatrix = mat4(cos(rotation), -sin(rotation), 0.0, 0.0,
+                               sin(rotation), cos(rotation),  0.0, 0.0,
+                               0.0,           0.0,            1.0, 0.0,
+                               0.0,           0.0,            0.0, 1.0);
+    mat4 translationMatrix = mat4(1.0, 0.0, 0.0, position.x - anchor.x,
+                                  0.0, 1.0, 0.0, position.y - anchor.y,
+                                  0.0, 0.0, 1.0, 0.0,
+                                  0.0, 0.0, 0.0, 1.0);
+    mat4 scaleMatrix = mat4(scale.x, 0.0,     0.0, 0.0,
+                            0.0,     scale.y, 0.0, 0.0,
+                            0.0,     0.0,     1.0, 0.0,
+                            0.0,     0.0,     0.0, 1.0);
+
+    gl_Position = projection * (gl_Vertex * scaleMatrix *
+                                rotationMatrix * translationMatrix);
+    gl_TexCoord[0] = gl_MultiTexCoord0;
+}