add support for background opacity in style

7 files changed, 25 insertions, 5 deletions

diff --git a/include/llmr/shader/plain_shader.hpp b/include/llmr/shader/plain_shader.hpp
index bf768f8845..d833375eb5 100644
--- a/include/llmr/shader/plain_shader.hpp
+++ b/include/llmr/shader/plain_shader.hpp
@@ -13,12 +13,15 @@ public:
 
     void setColor(float r, float g, float b, float a);
     void setColor(const std::array<float, 4>& color);
+    void setOpacity(float opacity);
 
 private:
     int32_t a_pos = -1;
 
     std::array<float, 4> color = {{}};
     int32_t u_color = -1;
+    float opacity = 0.0f;
+    float u_opacity = 0.0f;
 };
 
 }
diff --git a/include/llmr/style/properties.hpp b/include/llmr/style/properties.hpp
index 47b6ff195c..5632011779 100644
--- a/include/llmr/style/properties.hpp
+++ b/include/llmr/style/properties.hpp
@@ -128,11 +128,12 @@ struct TextProperties {
 
 struct BackgroundClass {
     Color color = {{ 1, 1, 1, 1 }};
+    FunctionProperty opacity = 1;
 };
 
-
 struct BackgroundProperties {
     Color color = {{ 1, 1, 1, 1 }};
+    float opacity = 1.0;
 };
 
 
diff --git a/src/renderer/painter.cpp b/src/renderer/painter.cpp
index 092f282f98..a04de17334 100644
--- a/src/renderer/painter.cpp
+++ b/src/renderer/painter.cpp
@@ -125,9 +125,9 @@ void Painter::prepareClippingMask() {
 
 void Painter::drawClippingMask(const mat4& matrix, uint8_t clip_id, bool opaque) {
     plainShader->setMatrix(matrix);
-    if (opaque) {
-        plainShader->setColor(style.computed.background.color);
-    }
+
+    plainShader->setColor(style.computed.background.color);
+    plainShader->setOpacity(style.computed.background.opacity);
 
     glStencilFunc(GL_ALWAYS, clip_id, 0xFF);
     glDrawArrays(GL_TRIANGLES, 0, (GLsizei)tileStencilBuffer.index());
diff --git a/src/shader/plain.fragment.glsl b/src/shader/plain.fragment.glsl
index 8df552c171..0761ea5e65 100644
--- a/src/shader/plain.fragment.glsl
+++ b/src/shader/plain.fragment.glsl
@@ -1,5 +1,6 @@
 uniform vec4 u_color;
+uniform float u_opacity;
 
 void main() {
-    gl_FragColor = u_color;
+    gl_FragColor = u_color * u_opacity;
 }
diff --git a/src/shader/plain_shader.cpp b/src/shader/plain_shader.cpp
index ac4b7edeb0..2b367dc501 100644
--- a/src/shader/plain_shader.cpp
+++ b/src/shader/plain_shader.cpp
@@ -20,11 +20,13 @@ PlainShader::PlainShader()
 
     u_matrix = glGetUniformLocation(program, "u_matrix");
     u_color = glGetUniformLocation(program, "u_color");
+    u_opacity = glGetUniformLocation(program, "u_opacity");
 
     // fprintf(stderr, "PlainShader:\n");
     // fprintf(stderr, "    - a_pos: %d\n", a_pos);
     // fprintf(stderr, "    - u_matrix: %d\n", u_matrix);
     // fprintf(stderr, "    - u_color: %d\n", u_color);
+    // fprintf(stderr, "    - u_opacity: %f\n", u_opacity);
 }
 
 void PlainShader::bind(char *offset) {
@@ -42,3 +44,11 @@ void PlainShader::setColor(const std::array<float, 4>& new_color) {
 void PlainShader::setColor(float r, float g, float b, float a) {
     setColor({{ r, g, b, a }});
 }
+
+void PlainShader::setOpacity(float new_opacity) {
+    if (opacity != new_opacity) {
+        glUniform1f(u_opacity, new_opacity);
+        fprintf(stderr, "opacity: %f\n", new_opacity);
+        opacity = new_opacity;
+    }
+}
diff --git a/src/style/style.cpp b/src/style/style.cpp
index 7e72623f9f..0a63e9d5b8 100644
--- a/src/style/style.cpp
+++ b/src/style/style.cpp
@@ -94,6 +94,7 @@ void Style::cascade(float z) {
 
         // Cascade background
         computed.background.color = sheetClass.background.color;
+        computed.background.opacity = sheetClass.background.opacity.evaluate<float>(z);
     }
 }
 
diff --git a/src/style/style_parser.cpp b/src/style/style_parser.cpp
index 0d2e371720..893e65ea70 100644
--- a/src/style/style_parser.cpp
+++ b/src/style/style_parser.cpp
@@ -509,6 +509,10 @@ BackgroundClass StyleParser::parseBackgroundClass(JSVal value) {
         klass.color = parseColor(value["color"]);
     }
 
+    if (value.HasMember("opacity")) {
+        klass.opacity = parseFunction(value["opacity"]);
+    }
+
     return klass;
 }