Shader:hasVariable;

src/api/l_graphics_shader.c

@@ -71,6 +71,14 @@ static int l_lovrShaderHasAttribute(lua_State* L) {
   return 1;
 }
 
+static int l_lovrShaderHasVariable(lua_State* L) {
+  Shader* shader = luax_checktype(L, 1, Shader);
+  const char* variable = luaL_checkstring(L, 2);
+  bool present = lovrShaderHasVariable(shader, variable);
+  lua_pushboolean(L, present);
+  return 1;
+}
+
 static int l_lovrShaderGetWorkgroupSize(lua_State* L) {
   Shader* shader = luax_checktype(L, 1, Shader);
 
@@ -133,6 +141,7 @@ const luaL_Reg lovrShader[] = {
   { "getType", l_lovrShaderGetType },
   { "hasStage", l_lovrShaderHasStage },
   { "hasAttribute", l_lovrShaderHasAttribute },
+  { "hasVariable", l_lovrShaderHasVariable },
   { "getWorkgroupSize", l_lovrShaderGetWorkgroupSize },
   { "getBufferFormat", l_lovrShaderGetBufferFormat },
   { NULL, NULL }

src/modules/graphics/graphics.c

@@ -3341,6 +3341,24 @@ bool lovrShaderHasAttribute(Shader* shader, const char* name, uint32_t location)
   return false;
 }
 
+bool lovrShaderHasVariable(Shader* shader, const char* name) {
+  uint32_t hash = (uint32_t) hash64(name, strlen(name));
+
+  for (uint32_t i = 0; i < shader->uniformCount; i++) {
+    if (shader->uniforms[i].hash == hash) {
+      return true;
+    }
+  }
+
+  for (uint32_t i = 0; i < shader->resourceCount; i++) {
+    if (shader->resources[i].hash == hash) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void lovrShaderGetWorkgroupSize(Shader* shader, uint32_t size[3]) {
   memcpy(size, shader->workgroupSize, 3 * sizeof(uint32_t));
 }

src/modules/graphics/graphics.h

@@ -333,6 +333,7 @@ void lovrShaderDestroy(void* ref);
 const ShaderInfo* lovrShaderGetInfo(Shader* shader);
 bool lovrShaderHasStage(Shader* shader, ShaderStage stage);
 bool lovrShaderHasAttribute(Shader* shader, const char* name, uint32_t location);
+bool lovrShaderHasVariable(Shader* shader, const char* name);
 void lovrShaderGetWorkgroupSize(Shader* shader, uint32_t size[3]);
 const DataField* lovrShaderGetBufferFormat(Shader* shader, const char* name, uint32_t* fieldCount);
 

test/lovr/graphics.lua

@@ -446,4 +446,22 @@ group('graphics', function()
       expect({ image:getPixel(0, 0) }).to.equal({ 0, 0, 1, 1 })
     end)
   end)
+
+  group('Shader', function()
+    test(':hasVariable', function()
+      shader = lovr.graphics.newShader([[
+        uniform vec3 position;
+        vec4 lovrmain() { return vec4(position, 1.); }
+      ]], [[
+        buffer Params { vec4 color; };
+        uniform texture2D image;
+        vec4 lovrmain() { return color; }
+      ]])
+
+      expect(shader:hasVariable('position')).to.equal(true)
+      expect(shader:hasVariable('unknown')).to.equal(false)
+      expect(shader:hasVariable('Params')).to.equal(true)
+      expect(shader:hasVariable('image')).to.equal(true)
+    end)
+  end)
 end)