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graphics/tinygl/matrix.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * This file is based on, or a modified version of code from TinyGL (C) 1997-2022 Fabrice Bellard,
+ * which is licensed under the MIT license (see LICENSE).
+ * It also has modifications by the ResidualVM-team, which are covered under the GPLv2 (or later).
+ */
+
+#define FORBIDDEN_SYMBOL_EXCEPTION_fprintf
+#define FORBIDDEN_SYMBOL_EXCEPTION_stderr
+
+#include "graphics/tinygl/zgl.h"
+
+namespace TinyGL {
+
+void GLContext::gl_print_matrix(const float *m) {
+	for (int i = 0; i < 4; i++) {
+		fprintf(stderr, "%f %f %f %f\n", m[i], m[4 + i], m[8 + i], m[12 + i]);
+	}
+}
+
+static inline void gl_matrix_update(GLContext *c) {
+	c->matrix_model_projection_updated |= (c->matrix_mode <= 1);
+}
+
+void GLContext::glopMatrixMode(GLParam *p) {
+	int mode = p[1].i;
+	switch (mode) {
+	case TGL_MODELVIEW:
+		matrix_mode = 0;
+		break;
+	case TGL_PROJECTION:
+		matrix_mode = 1;
+		break;
+	case TGL_TEXTURE:
+		matrix_mode = 2;
+		break;
+	default:
+		assert(0);
+	}
+}
+
+void GLContext::glopLoadMatrix(GLParam *p) {
+	Matrix4 *m;
+	GLParam *q;
+
+	m = matrix_stack_ptr[matrix_mode];
+	q = p + 1;
+
+	for (int i = 0; i < 4; i++) {
+		m->_m[0][i] = q[0].f;
+		m->_m[1][i] = q[1].f;
+		m->_m[2][i] = q[2].f;
+		m->_m[3][i] = q[3].f;
+		q += 4;
+	}
+
+	gl_matrix_update(this);
+}
+
+void GLContext::glopLoadIdentity(GLParam *) {
+	matrix_stack_ptr[matrix_mode]->identity();
+	gl_matrix_update(this);
+}
+
+void GLContext::glopMultMatrix(GLParam *p) {
+	Matrix4 m;
+	GLParam *q;
+	q = p + 1;
+
+	for (int i = 0; i < 4; i++) {
+		m._m[0][i] = q[0].f;
+		m._m[1][i] = q[1].f;
+		m._m[2][i] = q[2].f;
+		m._m[3][i] = q[3].f;
+		q += 4;
+	}
+
+	*matrix_stack_ptr[matrix_mode] *= m;
+
+	gl_matrix_update(this);
+}
+
+void GLContext::glopPushMatrix(GLParam *) {
+	int n = matrix_mode;
+	Matrix4 *m;
+
+	assert((matrix_stack_ptr[n] - matrix_stack[n] + 1) < matrix_stack_depth_max[n]);
+
+	m = ++matrix_stack_ptr[n];
+
+	m[0] = m[-1];
+
+	gl_matrix_update(this);
+}
+
+void GLContext::glopPopMatrix(GLParam *) {
+	int n = matrix_mode;
+
+	assert(matrix_stack_ptr[n] > matrix_stack[n]);
+	matrix_stack_ptr[n]--;
+	gl_matrix_update(this);
+}
+
+void GLContext::glopRotate(GLParam *p) {
+	Matrix4 m;
+	float u[3];
+	float angle;
+	int dir_code;
+
+	angle = (float)(p[1].f * (float)M_PI / 180.0);
+	u[0] = p[2].f;
+	u[1] = p[3].f;
+	u[2] = p[4].f;
+
+	// simple case detection
+	dir_code = ((u[0] != 0) << 2) | ((u[1] != 0) << 1) | (u[2] != 0);
+
+	switch (dir_code) {
+	case 0:
+		m.identity();
+		break;
+	case 4:
+		if (u[0] < 0)
+			angle = -angle;
+		m.rotation(angle, 0);
+		break;
+	case 2:
+		if (u[1] < 0)
+			angle = -angle;
+		m.rotation(angle, 1);
+		break;
+	case 1:
+		if (u[2] < 0)
+			angle = -angle;
+		m.rotation(angle, 2);
+		break;
+	default: {
+		float cost, sint;
+
+		// normalize vector
+		float len = u[0] * u[0] + u[1] * u[1] + u[2] * u[2];
+		if (len == 0.0f)
+			return;
+		len = 1.0f / sqrt(len);
+		u[0] *= len;
+		u[1] *= len;
+		u[2] *= len;
+
+		// store cos and sin values
+		cost = cos(angle);
+		sint = sin(angle);
+
+		// fill in the values
+		m._m[3][0] = 0.0f;
+		m._m[3][2] = 0.0f;
+		m._m[0][3] = 0.0f;
+		m._m[1][3] = 0.0f;
+		m._m[2][3] = 0.0f;
+		m._m[3][3] = 1.0f;
+
+		// do the math
+		m._m[0][0] = u[0] * u[0] + cost * (1 - u[0] * u[0]);
+		m._m[1][0] = u[0] * u[1] * (1 -cost) - u[2] * sint;
+		m._m[2][0] = u[2] * u[0] * (1 -cost) + u[1] * sint;
+		m._m[0][1] = u[0] * u[1] * (1 -cost) + u[2] * sint;
+		m._m[1][1] = u[1] * u[1] + cost * (1 - u[1] * u[1]);
+		m._m[2][1] = u[1] * u[2] * (1 - cost) - u[0] * sint;
+		m._m[0][2] = u[2] * u[0] * (1 - cost) - u[1] * sint;
+		m._m[1][2] = u[1] * u[2] * (1 - cost) + u[0] * sint;
+		m._m[2][2] = u[2] * u[2] + cost * (1 - u[2] * u[2]);
+	}
+	}
+
+	*matrix_stack_ptr[matrix_mode] *= m;
+
+	gl_matrix_update(this);
+}
+
+void GLContext::glopScale(GLParam *p) {
+	matrix_stack_ptr[matrix_mode]->scale(p[1].f, p[2].f, p[3].f);
+	gl_matrix_update(this);
+}
+
+void GLContext::glopTranslate(GLParam *p) {
+	matrix_stack_ptr[matrix_mode]->translate(p[1].f, p[2].f, p[3].f);
+	gl_matrix_update(this);
+}
+
+void GLContext::glopFrustum(GLParam *p) {
+	float left = p[1].f;
+	float right = p[2].f;
+	float bottom = p[3].f;
+	float top = p[4].f;
+	float nearp = p[5].f;
+	float farp = p[6].f;
+	Matrix4 m = Matrix4::frustum(left, right, bottom, top, nearp, farp);
+
+	*matrix_stack_ptr[matrix_mode] *= m;
+
+	gl_matrix_update(this);
+}
+
+void GLContext::glopOrtho(GLParam *p) {
+	float *r;
+	TinyGL::Matrix4 m;
+	float left = p[1].f;
+	float right = p[2].f;
+	float bottom = p[3].f;
+	float top = p[4].f;
+	float zNear = p[5].f;
+	float zFar = p[6].f;
+
+	float a = 2.0f / (right - left);
+	float b = 2.0f / (top - bottom);
+	float c = -2.0f / (zFar - zNear);
+
+	float tx = -(right + left) / (right - left);
+	float ty = -(top + bottom) / (top - bottom);
+	float tz = -(zFar + zNear) / (zFar - zNear);
+
+	r = &m._m[0][0];
+	r[0] = a; r[1] = 0; r[2] = 0; r[3] = tx;
+	r[4] = 0; r[5] = b; r[6] = 0; r[7] = ty;
+	r[8] = 0; r[9] = 0; r[10] = c; r[11] = tz;
+	r[12] = 0; r[13] = 0; r[14] = 0; r[15] = 1;
+
+	*matrix_stack_ptr[matrix_mode] *= m;
+	gl_matrix_update(this);
+}
+
+} // end of namespace TinyGL