[core] Use separate shaders for background and clipping

src/mbgl/shaders/background_pattern.cpp

@@ -0,0 +1,65 @@
+// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
+
+#include <mbgl/shaders/background_pattern.hpp>
+
+namespace mbgl {
+namespace shaders {
+
+const char* background_pattern::name = "background_pattern";
+const char* background_pattern::vertexSource = R"MBGL_SHADER(
+uniform mat4 u_matrix;
+uniform vec2 u_pattern_size_a;
+uniform vec2 u_pattern_size_b;
+uniform vec2 u_pixel_coord_upper;
+uniform vec2 u_pixel_coord_lower;
+uniform float u_scale_a;
+uniform float u_scale_b;
+uniform float u_tile_units_to_pixels;
+
+attribute vec2 a_pos;
+
+varying vec2 v_pos_a;
+varying vec2 v_pos_b;
+
+void main() {
+    gl_Position = u_matrix * vec4(a_pos, 0, 1);
+
+    v_pos_a = get_pattern_pos(u_pixel_coord_upper, u_pixel_coord_lower, u_scale_a * u_pattern_size_a, u_tile_units_to_pixels, a_pos);
+    v_pos_b = get_pattern_pos(u_pixel_coord_upper, u_pixel_coord_lower, u_scale_b * u_pattern_size_b, u_tile_units_to_pixels, a_pos);
+}
+
+)MBGL_SHADER";
+const char* background_pattern::fragmentSource = R"MBGL_SHADER(
+uniform vec2 u_pattern_tl_a;
+uniform vec2 u_pattern_br_a;
+uniform vec2 u_pattern_tl_b;
+uniform vec2 u_pattern_br_b;
+uniform vec2 u_texsize;
+uniform float u_mix;
+uniform float u_opacity;
+
+uniform sampler2D u_image;
+
+varying vec2 v_pos_a;
+varying vec2 v_pos_b;
+
+void main() {
+    vec2 imagecoord = mod(v_pos_a, 1.0);
+    vec2 pos = mix(u_pattern_tl_a / u_texsize, u_pattern_br_a / u_texsize, imagecoord);
+    vec4 color1 = texture2D(u_image, pos);
+
+    vec2 imagecoord_b = mod(v_pos_b, 1.0);
+    vec2 pos2 = mix(u_pattern_tl_b / u_texsize, u_pattern_br_b / u_texsize, imagecoord_b);
+    vec4 color2 = texture2D(u_image, pos2);
+
+    gl_FragColor = mix(color1, color2, u_mix) * u_opacity;
+
+#ifdef OVERDRAW_INSPECTOR
+    gl_FragColor = vec4(1.0);
+#endif
+}
+
+)MBGL_SHADER";
+
+} // namespace shaders
+} // namespace mbgl