Initial commit

graphics/tinygl/select.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).
+ */
+
+#include "graphics/tinygl/zgl.h"
+
+namespace TinyGL {
+
+TGLint GLContext::gl_RenderMode(TGLenum mode) {
+	int result = 0;
+
+	switch (render_mode) {
+	case TGL_RENDER:
+		break;
+	case TGL_SELECT:
+		if (select_overflow) {
+			result = -select_hits;
+		} else {
+			result = select_hits;
+		}
+		select_overflow = 0;
+		select_ptr = select_buffer;
+		name_stack_size = 0;
+		break;
+	default:
+		assert(0);
+	}
+	switch (mode) {
+	case TGL_RENDER:
+		render_mode = TGL_RENDER;
+		break;
+	case TGL_SELECT:
+		render_mode = TGL_SELECT;
+		assert(select_buffer != nullptr);
+		select_ptr = select_buffer;
+		select_hits = 0;
+		select_overflow = 0;
+		select_hit = nullptr;
+		break;
+	default:
+		assert(0);
+	}
+	return result;
+}
+
+void GLContext::gl_SelectBuffer(TGLsizei size, TGLuint *buffer) {
+	assert(render_mode != TGL_SELECT);
+
+	select_buffer = buffer;
+	select_size = size;
+}
+
+void GLContext::glopInitNames(GLParam *) {
+	if (render_mode == TGL_SELECT) {
+		name_stack_size = 0;
+		select_hit = nullptr;
+	}
+}
+
+void GLContext::glopPushName(GLParam *p) {
+	if (render_mode == TGL_SELECT) {
+		assert(name_stack_size < MAX_NAME_STACK_DEPTH);
+		name_stack[name_stack_size++] = p[1].i;
+		select_hit = nullptr;
+	}
+}
+
+void GLContext::glopPopName(GLParam *) {
+	if (render_mode == TGL_SELECT) {
+		assert(name_stack_size > 0);
+		name_stack_size--;
+		select_hit = nullptr;
+	}
+}
+
+void GLContext::glopLoadName(GLParam *p) {
+	if (render_mode == TGL_SELECT) {
+		assert(name_stack_size > 0);
+		name_stack[name_stack_size - 1] = p[1].i;
+		select_hit = nullptr;
+	}
+}
+
+void GLContext::gl_add_select(uint zmin, uint zmax) {
+	uint *ptr;
+	int n;
+
+	if (!select_overflow) {
+		if (!select_hit) {
+			n = name_stack_size;
+			if ((select_ptr - select_buffer + 3 + n) > select_size) {
+				select_overflow = 1;
+			} else {
+				ptr = select_ptr;
+				select_hit = ptr;
+				*ptr++ = name_stack_size;
+				*ptr++ = zmin;
+				*ptr++ = zmax;
+				for (int i = 0; i < n; i++)
+					*ptr++ = name_stack[i];
+				select_ptr = ptr;
+				select_hits++;
+			}
+		} else {
+			if (zmin < select_hit[1])
+				select_hit[1] = zmin;
+			if (zmax > select_hit[2])
+				select_hit[2] = zmax;
+		}
+	}
+}
+
+} // end of namespace TinyGL