OPENGL: Introduce ShaderManager to handle builtin shaders.

6 files changed, 106 insertions, 54 deletions

diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index 0a9b040f83..a8301482d3 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -58,7 +58,7 @@ OpenGLGraphicsManager::OpenGLGraphicsManager()
       , _osdAlpha(0), _osdFadeStartTime(0), _osd(nullptr)
 #endif
 #if !USE_FORCED_GLES
-      , _shader(nullptr), _projectionMatrix()
+      , _projectionMatrix()
 #endif
     {
 	memset(_gamePalette, 0, sizeof(_gamePalette));
@@ -73,7 +73,7 @@ OpenGLGraphicsManager::~OpenGLGraphicsManager() {
 	delete _osd;
 #endif
 #if !USE_FORCED_GLES
-	delete _shader;
+	ShaderManager::destroy();
 #endif
 }
 
@@ -790,9 +790,7 @@ void OpenGLGraphicsManager::setActualScreenSize(uint width, uint height) {
 #if !USE_FORCED_GLES
 		assert(sizeof(_projectionMatrix) == sizeof(orthoProjection));
 		memcpy(_projectionMatrix, orthoProjection, sizeof(_projectionMatrix));
-		if (_shader) {
-			_shader->activate(_projectionMatrix);
-		}
+		ShaderMan.query(ShaderManager::kDefault)->activate(_projectionMatrix);
 #endif
 #if !USE_FORCED_GL && !USE_FORCED_GLES && !USE_FORCED_GLES2
 	}
@@ -916,18 +914,9 @@ void OpenGLGraphicsManager::notifyContextCreate(const Graphics::PixelFormat &def
 	GL_CALL(glPixelStorei(GL_PACK_ALIGNMENT, 4));
 
 #if !USE_FORCED_GLES
-	if (!_shader) {
-		if (g_context.shadersSupported) {
-			_shader = new Shader(g_defaultVertexShader, g_defaultFragmentShader);
-		}
-	}
-#endif
-
-#if !USE_FORCED_GLES
-	if (_shader) {
-		// TODO: What do we do on failure?
-		_shader->recreate();
-		_shader->activate(_projectionMatrix);
+	if (g_context.shadersSupported) {
+		ShaderMan.notifyCreate();
+		ShaderMan.query(ShaderManager::kDefault)->activate(_projectionMatrix);
 	}
 #endif
 
@@ -981,8 +970,8 @@ void OpenGLGraphicsManager::notifyContextDestroy() {
 #endif
 
 #if !USE_FORCED_GLES
-	if (_shader) {
-		_shader->destroy();
+	if (g_context.shadersSupported) {
+		ShaderMan.notifyDestroy();
 	}
 #endif
 
diff --git a/backends/graphics/opengl/opengl-graphics.h b/backends/graphics/opengl/opengl-graphics.h
index 95ba4e7377..f3cd4c437f 100644
--- a/backends/graphics/opengl/opengl-graphics.h
+++ b/backends/graphics/opengl/opengl-graphics.h
@@ -533,11 +533,6 @@ private:
 	//
 
 	/**
-	 * Active shader.
-	 */
-	Shader *_shader;
-
-	/**
 	 * Projection matrix used.
 	 */
 	GLfloat _projectionMatrix[4*4];
diff --git a/backends/graphics/opengl/shader.cpp b/backends/graphics/opengl/shader.cpp
index e699262b8d..2f2d5d82eb 100644
--- a/backends/graphics/opengl/shader.cpp
+++ b/backends/graphics/opengl/shader.cpp
@@ -27,8 +27,14 @@
 #include "common/textconsole.h"
 #include "common/util.h"
 
+namespace Common {
+DECLARE_SINGLETON(OpenGL::ShaderManager);
+}
+
 namespace OpenGL {
 
+namespace {
+
 const char *const g_defaultVertexShader = 
 	"attribute vec4 position;\n"
 	"attribute vec2 texCoordIn;\n"
@@ -55,7 +61,20 @@ const char *const g_defaultFragmentShader =
 	"\tgl_FragColor = blendColor * texture2D(texture, texCoord);\n"
 	"}\n";
 
-namespace {
+const char *const g_lookUpFragmentShader =
+	"varying vec2 texCoord;\n"
+	"varying vec4 blendColor;\n"
+	"\n"
+	"uniform sampler2D texture;\n"
+	"uniform sampler2D palette;\n"
+	"\n"
+	"const float adjustFactor = 255.0 / 256.0 + 1.0 / (2.0 * 256.0);"
+	"\n"
+	"void main(void) {\n"
+	"\tvec4 index = texture2D(texture, texCoord);\n"
+	"\tgl_FragColor = blendColor * texture2D(palette, vec2(index.a * adjustFactor, 0.0));\n"
+	"}\n";
+
 
 // Taken from: https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_03#OpenGL_ES_2_portability
 const char *const g_precisionDefines =
@@ -219,6 +238,38 @@ GLshader Shader::compileShader(const char *source, GLenum shaderType) {
 	return handle;
 }
 
+ShaderManager::ShaderManager() {
+	_builtIn[kDefault] = new Shader(g_defaultVertexShader, g_defaultFragmentShader);
+	_builtIn[kCLUT8LookUp] = new Shader(g_defaultVertexShader, g_lookUpFragmentShader);
+}
+
+ShaderManager::~ShaderManager() {
+	for (int i = 0; i < ARRAYSIZE(_builtIn); ++i) {
+		delete _builtIn[i];
+	}
+}
+
+void ShaderManager::notifyDestroy() {
+	for (int i = 0; i < ARRAYSIZE(_builtIn); ++i) {
+		_builtIn[i]->destroy();
+	}
+}
+
+void ShaderManager::notifyCreate() {
+	for (int i = 0; i < ARRAYSIZE(_builtIn); ++i) {
+		_builtIn[i]->recreate();
+	}
+}
+
+Shader *ShaderManager::query(ShaderUsage shader) const {
+	if (shader == kMaxUsages) {
+		warning("OpenGL: ShaderManager::query used with kMaxUsages");
+		return nullptr;
+	}
+
+	return _builtIn[shader];
+}
+
 } // End of namespace OpenGL
 
 #endif // !USE_FORCED_GLES
diff --git a/backends/graphics/opengl/shader.h b/backends/graphics/opengl/shader.h
index 98a2a2859b..e5dbcacfad 100644
--- a/backends/graphics/opengl/shader.h
+++ b/backends/graphics/opengl/shader.h
@@ -28,6 +28,7 @@
 #if !USE_FORCED_GLES
 
 #include "common/str.h"
+#include "common/singleton.h"
 
 namespace OpenGL {
 
@@ -37,9 +38,6 @@ enum {
 	kColorAttribLocation    = 2
 };
 
-extern const char *const g_defaultVertexShader;
-extern const char *const g_defaultFragmentShader;
-
 class Shader {
 public:
 	Shader(const Common::String &vertex, const Common::String &fragment);
@@ -121,8 +119,47 @@ protected:
 	static GLshader compileShader(const char *source, GLenum shaderType);
 };
 
+class ShaderManager : public Common::Singleton<ShaderManager> {
+public:
+	enum ShaderUsage {
+		/** Default shader implementing the GL fixed-function pipeline. */
+		kDefault = 0,
+
+		/** CLUT8 look up shader. */
+		kCLUT8LookUp,
+
+		/** Number of built-in shaders. Should not be used for query. */
+		kMaxUsages
+	};
+
+	/**
+	 * Notify shader manager about context destruction.
+	 */
+	void notifyDestroy();
+
+	/**
+	 * Notify shader manager about context creation.
+	 */
+	void notifyCreate();
+
+	/**
+	 * Query a built-in shader.
+	 */
+	Shader *query(ShaderUsage shader) const;
+
+private:
+	friend class Common::Singleton<SingletonBaseType>;
+	ShaderManager();
+	~ShaderManager();
+
+	Shader *_builtIn[kMaxUsages];
+};
+
 } // End of namespace OpenGL
 
+/** Shortcut for accessing the font manager. */
+#define ShaderMan (OpenGL::ShaderManager::instance())
+
 #endif // !USE_FORCED_GLES
 
 #endif
diff --git a/backends/graphics/opengl/texture.cpp b/backends/graphics/opengl/texture.cpp
index 61e8dc37b3..828dade0be 100644
--- a/backends/graphics/opengl/texture.cpp
+++ b/backends/graphics/opengl/texture.cpp
@@ -506,21 +506,6 @@ void TextureRGB555::updateTexture() {
 #endif // !USE_FORCED_GL
 
 #if !USE_FORCED_GLES
-namespace {
-const char *const g_lookUpFragmentShader =
-	"varying vec2 texCoord;\n"
-	"varying vec4 blendColor;\n"
-	"\n"
-	"uniform sampler2D texture;\n"
-	"uniform sampler2D palette;\n"
-	"\n"
-	"const float adjustFactor = 255.0 / 256.0 + 1.0 / (2.0 * 256.0);"
-	"\n"
-	"void main(void) {\n"
-	"\tvec4 index = texture2D(texture, texCoord);\n"
-	"\tgl_FragColor = blendColor * texture2D(palette, vec2(index.a * adjustFactor, 0.0));\n"
-	"}\n";
-} // End of anonymous namespace
 
 // _clut8Texture needs 8 bits internal precision, otherwise graphics glitches
 // can occur. GL_ALPHA does not have any internal precision requirements.
@@ -532,20 +517,17 @@ TextureCLUT8GPU::TextureCLUT8GPU()
       _paletteTexture(GL_RGBA, GL_RGBA, GL_UNSIGNED_BYTE),
       _glTexture(GL_RGBA, GL_RGBA, GL_UNSIGNED_BYTE),
       _glFBO(0), _clut8Vertices(), _projectionMatrix(),
-      _lookUpShader(nullptr), _paletteLocation(-1),
+      _paletteLocation(-1),
       _clut8Data(), _userPixelData(), _palette(), _paletteDirty(false) {
 	// Allocate space for 256 colors.
 	_paletteTexture.setSize(256, 1);
 
-	_lookUpShader = new Shader(g_defaultVertexShader, g_lookUpFragmentShader);
-	_lookUpShader->recreate();
-	_paletteLocation = _lookUpShader->getUniformLocation("palette");
+	_paletteLocation = ShaderMan.query(ShaderManager::kCLUT8LookUp)->getUniformLocation("palette");
 
 	setupFBO();
 }
 
 TextureCLUT8GPU::~TextureCLUT8GPU() {
-	delete _lookUpShader;
 	GL_CALL_SAFE(glDeleteFramebuffers, (1, &_glFBO));
 	_clut8Data.free();
 }
@@ -554,7 +536,6 @@ void TextureCLUT8GPU::destroy() {
 	_clut8Texture.destroy();
 	_paletteTexture.destroy();
 	_glTexture.destroy();
-	_lookUpShader->destroy();
 
 	GL_CALL(glDeleteFramebuffers(1, &_glFBO));
 	_glFBO = 0;
@@ -564,8 +545,7 @@ void TextureCLUT8GPU::recreate() {
 	_clut8Texture.create();
 	_paletteTexture.create();
 	_glTexture.create();
-	_lookUpShader->recreate();
-	_paletteLocation = _lookUpShader->getUniformLocation("palette");
+	_paletteLocation = ShaderMan.query(ShaderManager::kCLUT8LookUp)->getUniformLocation("palette");
 	setupFBO();
 
 	// In case image date exists assure it will be completely refreshed next
@@ -743,8 +723,9 @@ void TextureCLUT8GPU::lookUpColors() {
 	_clut8Texture.bind();
 
 	// Do color look up.
-	_lookUpShader->activate(_projectionMatrix);
-	_lookUpShader->setUniformI(_paletteLocation, 1);
+	Shader *lookUpShader = ShaderMan.query(ShaderManager::kCLUT8LookUp);
+	lookUpShader->activate(_projectionMatrix);
+	lookUpShader->setUniformI(_paletteLocation, 1);
 	g_context.activePipeline->setDrawCoordinates(_clut8Vertices, _clut8Texture.getTexCoords());
 	GL_CALL(glDrawArrays(GL_TRIANGLE_STRIP, 0, 4));
 
diff --git a/backends/graphics/opengl/texture.h b/backends/graphics/opengl/texture.h
index 959281539f..5f586f6a2f 100644
--- a/backends/graphics/opengl/texture.h
+++ b/backends/graphics/opengl/texture.h
@@ -366,7 +366,6 @@ private:
 	GLfloat _clut8Vertices[4*2];
 	GLfloat _projectionMatrix[4*4];
 
-	Shader *_lookUpShader;
 	GLint _paletteLocation;
 
 	Graphics::Surface _clut8Data;