gl: Add an enum for tex units

Instead of hardcoding 0 for source and 1 for mask, use an enum. It's
also clearer when functions take a cairo_gl_tex_t argument instead of a
GLuint.

3 files changed, 27 insertions, 32 deletions

diff --git a/src/cairo-gl-composite.c b/src/cairo-gl-composite.c
index 55154c3a..ecd1b570 100644
--- a/src/cairo-gl-composite.c
+++ b/src/cairo-gl-composite.c
@@ -607,7 +607,7 @@ _cairo_gl_texture_set_attributes (cairo_gl_context_t         *ctx,
 
 static void
 _cairo_gl_context_setup_operand (cairo_gl_context_t *ctx,
-                                 GLuint              tex_unit,
+                                 cairo_gl_tex_t      tex_unit,
                                  cairo_gl_operand_t *operand,
                                  unsigned int        vertex_offset)
 {
@@ -660,14 +660,14 @@ _cairo_gl_context_setup_operand (cairo_gl_context_t *ctx,
 
 static void
 _cairo_gl_context_destroy_operand (cairo_gl_context_t *ctx,
-                                   GLuint              tex_unit)
+                                   cairo_gl_tex_t tex_unit)
 {
   memset (&ctx->operands[tex_unit], 0, sizeof (cairo_gl_operand_t));
 }
 
 static void
 _cairo_gl_operand_setup_fixed (cairo_gl_operand_t *operand,
-                               GLuint tex_unit)
+                               cairo_gl_tex_t tex_unit)
 {
     switch (operand->type) {
     case CAIRO_GL_OPERAND_CONSTANT:
@@ -709,7 +709,7 @@ _cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
 
-    _cairo_gl_operand_setup_fixed (&setup->src, 0);
+    _cairo_gl_operand_setup_fixed (&setup->src, CAIRO_GL_TEX_SOURCE);
 }
 
 /* Swizzles the source for creating the "source alpha" value
@@ -751,7 +751,7 @@ _cairo_gl_set_component_alpha_mask_operand (cairo_gl_context_t *ctx,
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
 
-    _cairo_gl_operand_setup_fixed (&setup->mask, 1);
+    _cairo_gl_operand_setup_fixed (&setup->mask, CAIRO_GL_TEX_MASK);
 }
 
 static void
@@ -775,7 +775,7 @@ _cairo_gl_set_mask_operand (cairo_gl_context_t *ctx,
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_ALPHA);
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
 
-    _cairo_gl_operand_setup_fixed (&setup->mask, 1);
+    _cairo_gl_operand_setup_fixed (&setup->mask, CAIRO_GL_TEX_MASK);
 }
 
 static void
@@ -1004,8 +1004,8 @@ _cairo_gl_composite_begin (cairo_gl_composite_t *setup,
     glVertexPointer (2, GL_FLOAT, ctx->vertex_size, NULL);
     glEnableClientState (GL_VERTEX_ARRAY);
 
-    _cairo_gl_context_setup_operand (ctx, 0, &setup->src, dst_size);
-    _cairo_gl_context_setup_operand (ctx, 1, &setup->mask, dst_size + src_size);
+    _cairo_gl_context_setup_operand (ctx, CAIRO_GL_TEX_SOURCE, &setup->src, dst_size);
+    _cairo_gl_context_setup_operand (ctx, CAIRO_GL_TEX_MASK, &setup->mask, dst_size + src_size);
 
     _cairo_gl_set_src_operand (ctx, setup);
     if (setup->has_component_alpha)
@@ -1250,8 +1250,8 @@ _cairo_gl_composite_end (cairo_gl_context_t *ctx,
     glDisable (GL_TEXTURE_1D);
     glDisable (ctx->tex_target);
 
-    _cairo_gl_context_destroy_operand (ctx, 0);
-    _cairo_gl_context_destroy_operand (ctx, 1);
+    _cairo_gl_context_destroy_operand (ctx, CAIRO_GL_TEX_SOURCE);
+    _cairo_gl_context_destroy_operand (ctx, CAIRO_GL_TEX_MASK);
 
     ctx->pre_shader = NULL;
 
diff --git a/src/cairo-gl-private.h b/src/cairo-gl-private.h
index 070f79ce..9e653f48 100644
--- a/src/cairo-gl-private.h
+++ b/src/cairo-gl-private.h
@@ -88,6 +88,11 @@ typedef struct cairo_gl_glyph_cache {
     cairo_surface_pattern_t pattern;
 } cairo_gl_glyph_cache_t;
 
+typedef enum cairo_gl_tex {
+    CAIRO_GL_TEX_SOURCE = 0,
+    CAIRO_GL_TEX_MASK = 1
+} cairo_gl_tex_t;
+
 typedef enum cairo_gl_operand_type {
     CAIRO_GL_OPERAND_NONE,
     CAIRO_GL_OPERAND_CONSTANT,
diff --git a/src/cairo-gl-shaders.c b/src/cairo-gl-shaders.c
index fdd4b673..2b551192 100644
--- a/src/cairo-gl-shaders.c
+++ b/src/cairo-gl-shaders.c
@@ -87,7 +87,7 @@ typedef struct cairo_gl_shader_impl {
     void
     (*bind_texture) (cairo_gl_shader_t *shader,
 		     const char *name,
-		     GLuint tex_unit);
+		     cairo_gl_tex_t tex_unit);
 
     void
     (*use) (cairo_gl_shader_t *shader);
@@ -243,7 +243,7 @@ bind_matrix_arb (cairo_gl_shader_t *shader,
 static void
 bind_texture_arb (cairo_gl_shader_t *shader,
 		  const char *name,
-		  GLuint tex_unit)
+		  cairo_gl_tex_t tex_unit)
 {
     GLint location = glGetUniformLocationARB (shader->program, name);
     assert (location != -1);
@@ -397,7 +397,7 @@ bind_matrix_core_2_0 (cairo_gl_shader_t *shader, const char *name, cairo_matrix_
 }
 
 static void
-bind_texture_core_2_0 (cairo_gl_shader_t *shader, const char *name, GLuint tex_unit)
+bind_texture_core_2_0 (cairo_gl_shader_t *shader, const char *name, cairo_gl_tex_t tex_unit)
 {
     GLint location = glGetUniformLocation (shader->program, name);
     assert (location != -1);
@@ -559,12 +559,6 @@ _cairo_gl_shader_fini (cairo_gl_context_t *ctx,
         ctx->shader_impl->destroy_program (shader->program);
 }
 
-typedef enum cairo_gl_operand_name {
-  CAIRO_GL_OPERAND_SOURCE,
-  CAIRO_GL_OPERAND_MASK,
-  CAIRO_GL_OPERAND_DEST
-} cairo_gl_operand_name_t;
-
 static const char *operand_names[] = { "source", "mask", "dest" };
 
 static cairo_gl_var_type_t
@@ -589,7 +583,7 @@ cairo_gl_operand_get_var_type (cairo_gl_operand_type_t type)
 static void
 cairo_gl_shader_emit_variable (cairo_output_stream_t *stream,
                                cairo_gl_var_type_t type,
-                               cairo_gl_operand_name_t name)
+                               cairo_gl_tex_t name)
 {
     switch (type) {
     default:
@@ -612,7 +606,7 @@ cairo_gl_shader_emit_variable (cairo_output_stream_t *stream,
 static void
 cairo_gl_shader_emit_vertex (cairo_output_stream_t *stream,
                              cairo_gl_var_type_t type,
-                             cairo_gl_operand_name_t name)
+                             cairo_gl_tex_t name)
 {
     switch (type) {
     default:
@@ -643,18 +637,16 @@ cairo_gl_shader_get_vertex_source (cairo_gl_var_type_t src,
     unsigned int length;
     cairo_status_t status;
 
-    cairo_gl_shader_emit_variable (stream, src, CAIRO_GL_OPERAND_SOURCE);
-    cairo_gl_shader_emit_variable (stream, mask, CAIRO_GL_OPERAND_MASK);
-    cairo_gl_shader_emit_variable (stream, dest, CAIRO_GL_OPERAND_DEST);
+    cairo_gl_shader_emit_variable (stream, src, CAIRO_GL_TEX_SOURCE);
+    cairo_gl_shader_emit_variable (stream, mask, CAIRO_GL_TEX_MASK);
 
     _cairo_output_stream_printf (stream,
 				 "void main()\n"
 				 "{\n"
 				 "    gl_Position = ftransform();\n");
 
-    cairo_gl_shader_emit_vertex (stream, src, CAIRO_GL_OPERAND_SOURCE);
-    cairo_gl_shader_emit_vertex (stream, mask, CAIRO_GL_OPERAND_MASK);
-    cairo_gl_shader_emit_vertex (stream, dest, CAIRO_GL_OPERAND_DEST);
+    cairo_gl_shader_emit_vertex (stream, src, CAIRO_GL_TEX_SOURCE);
+    cairo_gl_shader_emit_vertex (stream, mask, CAIRO_GL_TEX_MASK);
 
     _cairo_output_stream_write (stream,
 				"}\n\0", 3);
@@ -671,7 +663,7 @@ static void
 cairo_gl_shader_emit_color (cairo_output_stream_t *stream,
                             GLuint tex_target,
                             cairo_gl_operand_type_t type,
-                            cairo_gl_operand_name_t name)
+                            cairo_gl_tex_t name)
 {
     const char *namestr = operand_names[name];
     const char *rectstr = (tex_target == GL_TEXTURE_RECTANGLE_EXT ? "Rect" : "");
@@ -781,10 +773,8 @@ cairo_gl_shader_get_fragment_source (GLuint tex_target,
     unsigned int length;
     cairo_status_t status;
 
-    cairo_gl_shader_emit_color (stream, tex_target, src, CAIRO_GL_OPERAND_SOURCE);
-    cairo_gl_shader_emit_color (stream, tex_target, mask, CAIRO_GL_OPERAND_MASK);
-    if (dest != CAIRO_GL_OPERAND_NONE)
-      cairo_gl_shader_emit_color (stream, tex_target, dest, CAIRO_GL_OPERAND_DEST);
+    cairo_gl_shader_emit_color (stream, tex_target, src, CAIRO_GL_TEX_SOURCE);
+    cairo_gl_shader_emit_color (stream, tex_target, mask, CAIRO_GL_TEX_MASK);
 
     _cairo_output_stream_printf (stream,
         "void main()\n"