M src/platform/opengl/gles2.c → src/platform/opengl/gles2.c

@@ -16,6 +16,15 @@ "	gl_Position = position;\n"
 	"	texCoord = (position.st + vec2(1.0, -1.0)) * vec2(0.46875, -0.3125);\n"
 	"}";
 
+static const char* const _nullVertexShader =
+	"attribute vec4 position;\n"
+	"varying vec2 texCoord;\n"
+
+	"void main() {\n"
+	"	gl_Position = position * vec4(1.0, 1.0, 1.0, 1.0);\n"
+	"	texCoord = (position.st + vec2(1.0, 1.0)) * vec2(0.5, 0.5);\n"
+	"}";
+
 static const char* const _fragmentShader =
 	"varying vec2 texCoord;\n"
 	"uniform sampler2D tex;\n"
@@ -56,16 +65,23 @@
 	context->program = glCreateProgram();
 	context->fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
 	context->vertexShader = glCreateShader(GL_VERTEX_SHADER);
+	context->nullVertexShader = glCreateShader(GL_VERTEX_SHADER);
 
 	glShaderSource(context->fragmentShader, 1, (const GLchar**) &_fragmentShader, 0);
 	glShaderSource(context->vertexShader, 1, (const GLchar**) &_vertexShader, 0);
+	glShaderSource(context->nullVertexShader, 1, (const GLchar**) &_nullVertexShader, 0);
 	glAttachShader(context->program, context->vertexShader);
 	glAttachShader(context->program, context->fragmentShader);
 	char log[1024];
 	glCompileShader(context->fragmentShader);
 	glCompileShader(context->vertexShader);
+	glCompileShader(context->nullVertexShader);
 	glGetShaderInfoLog(context->fragmentShader, 1024, 0, log);
+	printf("%s\n", log);
 	glGetShaderInfoLog(context->vertexShader, 1024, 0, log);
+	printf("%s\n", log);
+	glGetShaderInfoLog(context->nullVertexShader, 1024, 0, log);
+	printf("%s\n", log);
 	glLinkProgram(context->program);
 	glGetProgramInfoLog(context->program, 1024, 0, log);
 	printf("%s\n", log);
@@ -79,6 +95,7 @@ struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
 	glDeleteTextures(1, &context->tex);
 	glDeleteShader(context->fragmentShader);
 	glDeleteShader(context->vertexShader);
+	glDeleteShader(context->nullVertexShader);
 	glDeleteProgram(context->program);
 }
 
@@ -106,10 +123,27 @@ }
 
 void GBAGLES2ContextDrawFrame(struct VideoBackend* v) {
 	struct GBAGLES2Context* context = (struct GBAGLES2Context*) v;
-	glUseProgram(context->program);
-	glUniform1i(context->texLocation, 0);
 	glActiveTexture(GL_TEXTURE0);
 	glBindTexture(GL_TEXTURE_2D, context->tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, v->filter ? GL_LINEAR : GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, v->filter ? GL_LINEAR : GL_NEAREST);
+
+	if (context->shader) {
+		GLint viewport[4];
+		glGetIntegerv(GL_VIEWPORT, viewport);
+		glViewport(0, 0, context->shader->width, context->shader->height);
+		glBindFramebuffer(GL_FRAMEBUFFER, context->shader->fbo);
+		glUseProgram(context->shader->program);
+		glUniform1i(context->shader->texLocation, 0);
+		glVertexAttribPointer(context->shader->positionLocation, 2, GL_FLOAT, GL_FALSE, 0, _vertices);
+		glEnableVertexAttribArray(context->shader->positionLocation);
+		glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+		glBindFramebuffer(GL_FRAMEBUFFER, 0);
+		glBindTexture(GL_TEXTURE_2D, context->shader->tex);
+		glViewport(viewport[0], viewport[1], viewport[2], viewport[3]);
+	}
+	glUseProgram(context->program);
+	glUniform1i(context->texLocation, 0);
 	glVertexAttribPointer(context->positionLocation, 2, GL_FLOAT, GL_FALSE, 0, _vertices);
 	glEnableVertexAttribArray(context->positionLocation);
 	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
@@ -140,4 +174,62 @@ context->d.postFrame = GBAGLES2ContextPostFrame;
 	context->d.drawFrame = GBAGLES2ContextDrawFrame;
 	context->d.setMessage = 0;
 	context->d.clearMessage = 0;
+	context->shader = 0;
+}
+
+void GBAGLES2ShaderInit(struct GBAGLES2Shader* shader, const char* src, int width, int height, bool filter) {
+	shader->width = width > 0 ? width : 256;
+	shader->height = height > 0 ? height : 256;
+	glGenFramebuffers(1, &shader->fbo);
+	glBindFramebuffer(GL_FRAMEBUFFER, shader->fbo);
+
+	glGenTextures(1, &shader->tex);
+	glBindTexture(GL_TEXTURE_2D, shader->tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter ? GL_LINEAR : GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter ? GL_LINEAR : GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, shader->width, shader->height, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
+
+	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, shader->tex, 0);
+	shader->program = glCreateProgram();
+	shader->fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+	glShaderSource(shader->fragmentShader, 1, (const GLchar**) &src, 0);
+	glAttachShader(shader->program, shader->fragmentShader);
+	glCompileShader(shader->fragmentShader);
+	char log[1024];
+	glGetShaderInfoLog(shader->fragmentShader, 1024, 0, log);
+	glBindFramebuffer(GL_FRAMEBUFFER, 0);
+}
+
+void GBAGLES2ShaderDeinit(struct GBAGLES2Shader* shader) {
+	glDeleteTextures(1, &shader->tex);
+	glDeleteShader(shader->fragmentShader);
+	glDeleteProgram(shader->program);
+}
+
+void GBAGLES2ShaderAttach(struct GBAGLES2Context* context, struct GBAGLES2Shader* shader) {
+	if (context->shader) {
+		if (context->shader == shader) {
+			return;
+		}
+		GBAGLES2ShaderDetach(context);
+	}
+	context->shader = shader;
+	glAttachShader(shader->program, context->nullVertexShader);
+
+	char log[1024];
+	glLinkProgram(shader->program);
+	glGetProgramInfoLog(shader->program, 1024, 0, log);
+	printf("%s\n", log);
+	shader->texLocation = glGetUniformLocation(shader->program, "tex");
+	shader->positionLocation = glGetAttribLocation(shader->program, "position");
+}
+
+void GBAGLES2ShaderDetach(struct GBAGLES2Context* context) {
+	if (!context->shader) {
+		return;
+	}
+	glDetachShader(context->shader->program, context->nullVertexShader);
+	context->shader = 0;
 }

M src/platform/opengl/gles2.h → src/platform/opengl/gles2.h

@@ -18,18 +18,37 @@ #endif
 
 #include "platform/video-backend.h"
 
+struct GBAGLES2Shader {
+	unsigned width;
+	unsigned height;
+	GLuint tex;
+	GLuint fbo;
+	GLuint fragmentShader;
+	GLuint program;
+	GLuint texLocation;
+	GLuint positionLocation;
+};
+
 struct GBAGLES2Context {
 	struct VideoBackend d;
 
 	GLuint tex;
 	GLuint fragmentShader;
 	GLuint vertexShader;
+	GLuint nullVertexShader;
 	GLuint program;
 	GLuint bufferObject;
 	GLuint texLocation;
 	GLuint positionLocation;
+
+	struct GBAGLES2Shader* shader;
 };
 
 void GBAGLES2ContextCreate(struct GBAGLES2Context*);
+
+void GBAGLES2ShaderInit(struct GBAGLES2Shader*, const char*, int width, int height, bool filter);
+void GBAGLES2ShaderDeinit(struct GBAGLES2Shader*);
+void GBAGLES2ShaderAttach(struct GBAGLES2Context*, struct GBAGLES2Shader*);
+void GBAGLES2ShaderDetach(struct GBAGLES2Context*);
 
 #endif