1/* Copyright (c) 2013-2015 Jeffrey Pfau
  2 *
  3 * This Source Code Form is subject to the terms of the Mozilla Public
  4 * License, v. 2.0. If a copy of the MPL was not distributed with this
  5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  6#include "gl.h"
  7
  8#include <mgba-util/math.h>
  9
 10static const GLint _glVertices[] = {
 11	0, 0,
 12	256, 0,
 13	256, 256,
 14	0, 256
 15};
 16
 17static const GLint _glTexCoords[] = {
 18	0, 0,
 19	1, 0,
 20	1, 1,
 21	0, 1
 22};
 23
 24static void mGLContextInit(struct VideoBackend* v, WHandle handle) {
 25	UNUSED(handle);
 26	struct mGLContext* context = (struct mGLContext*) v;
 27	v->width = 1;
 28	v->height = 1;
 29	glGenTextures(2, context->tex);
 30	glBindTexture(GL_TEXTURE_2D, context->tex[0]);
 31	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 32#ifndef _WIN32
 33	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 34	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 35#endif
 36	glBindTexture(GL_TEXTURE_2D, context->tex[1]);
 37	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 38#ifndef _WIN32
 39	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 40	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 41#endif
 42	context->activeTex = 0;
 43}
 44
 45static void mGLContextSetDimensions(struct VideoBackend* v, unsigned width, unsigned height) {
 46	struct mGLContext* context = (struct mGLContext*) v;
 47	if (width == v->width && height == v->height) {
 48		return;
 49	}
 50	v->width = width;
 51	v->height = height;
 52
 53	glBindTexture(GL_TEXTURE_2D, context->tex[0]);
 54#ifdef COLOR_16_BIT
 55#ifdef COLOR_5_6_5
 56	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, 0);
 57#else
 58	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, 0);
 59#endif
 60#elif defined(__BIG_ENDIAN__)
 61	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, 0);
 62#else
 63	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
 64#endif
 65
 66	glBindTexture(GL_TEXTURE_2D, context->tex[1]);
 67#ifdef COLOR_16_BIT
 68#ifdef COLOR_5_6_5
 69	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, 0);
 70#else
 71	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, 0);
 72#endif
 73#elif defined(__BIG_ENDIAN__)
 74	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, 0);
 75#else
 76	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, toPow2(width), toPow2(height), 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
 77#endif
 78}
 79
 80static void mGLContextDeinit(struct VideoBackend* v) {
 81	struct mGLContext* context = (struct mGLContext*) v;
 82	glDeleteTextures(2, context->tex);
 83}
 84
 85static void mGLContextResized(struct VideoBackend* v, unsigned w, unsigned h) {
 86	unsigned drawW = w;
 87	unsigned drawH = h;
 88	if (v->lockAspectRatio) {
 89		lockAspectRatioUInt(v->width, v->height, &drawW, &drawH);
 90	}
 91	if (v->lockIntegerScaling) {
 92		lockIntegerRatioUInt(v->width, &drawW);
 93		lockIntegerRatioUInt(v->height, &drawH);
 94	}
 95	glMatrixMode(GL_MODELVIEW);
 96	glLoadIdentity();
 97	glClearColor(0, 0, 0, 0);
 98	glClear(GL_COLOR_BUFFER_BIT);
 99	glViewport((w - drawW) / 2, (h - drawH) / 2, drawW, drawH);
100}
101
102static void mGLContextClear(struct VideoBackend* v) {
103	UNUSED(v);
104	glClearColor(0, 0, 0, 0);
105	glClear(GL_COLOR_BUFFER_BIT);
106}
107
108void mGLContextDrawFrame(struct VideoBackend* v) {
109	struct mGLContext* context = (struct mGLContext*) v;
110	glEnable(GL_TEXTURE_2D);
111	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
112	glEnableClientState(GL_VERTEX_ARRAY);
113	glVertexPointer(2, GL_INT, 0, _glVertices);
114	glTexCoordPointer(2, GL_INT, 0, _glTexCoords);
115	glMatrixMode(GL_PROJECTION);
116	glLoadIdentity();
117	glOrtho(0, v->width, v->height, 0, 0, 1);
118	glMatrixMode(GL_MODELVIEW);
119	glLoadIdentity();
120	if (v->interframeBlending) {
121		glBlendFunc(GL_CONSTANT_ALPHA, GL_ONE_MINUS_CONSTANT_ALPHA);
122		glBlendColor(1, 1, 1, 0.5);
123		glBindTexture(GL_TEXTURE_2D, context->tex[context->activeTex ^ 1]);
124		if (v->filter) {
125			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
126			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
127		} else {
128			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
129			glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
130		}
131		glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
132		glEnable(GL_BLEND);
133	}
134	glBindTexture(GL_TEXTURE_2D, context->tex[context->activeTex]);
135	if (v->filter) {
136		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
137		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
138	} else {
139		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
140		glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
141	}
142	glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
143	glDisable(GL_BLEND);
144}
145
146void mGLContextPostFrame(struct VideoBackend* v, const void* frame) {
147	struct mGLContext* context = (struct mGLContext*) v;
148	context->activeTex ^= 1;
149	glBindTexture(GL_TEXTURE_2D, context->tex[context->activeTex]);
150#ifdef COLOR_16_BIT
151#ifdef COLOR_5_6_5
152	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, v->width, v->height, GL_RGB, GL_UNSIGNED_SHORT_5_6_5, frame);
153#else
154	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, v->width, v->height, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, frame);
155#endif
156#elif defined(__BIG_ENDIAN__)
157	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, v->width, v->height, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, frame);
158#else
159	glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, v->width, v->height,  GL_RGBA, GL_UNSIGNED_BYTE, frame);
160#endif
161}
162
163void mGLContextCreate(struct mGLContext* context) {
164	context->d.init = mGLContextInit;
165	context->d.deinit = mGLContextDeinit;
166	context->d.setDimensions = mGLContextSetDimensions;
167	context->d.resized = mGLContextResized;
168	context->d.swap = 0;
169	context->d.clear = mGLContextClear;
170	context->d.postFrame = mGLContextPostFrame;
171	context->d.drawFrame = mGLContextDrawFrame;
172	context->d.setMessage = 0;
173	context->d.clearMessage = 0;
174}