Initial import

1 files changed, 647 insertions, 0 deletions

diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..78050f3
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,647 @@
+/*
+ * Copyright © 2009 Ian D. Romanick
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+#include <math.h>
+#include <GL/glew.h>
+#include <SDL.h>
+
+#include <glu3.h>
+
+#include "shader.h"
+
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+static SDL_Surface *my_surf = NULL;
+
+static bool anim = true;
+static bool done = false;
+
+static float y_angle = 0.0f;
+static float eye_distance = 15.0f;
+static float fov = 45.0f;
+
+static Uint32 t0;
+
+static GLuint bo;
+
+static GLUmat4 projection_matrix;
+
+class complex_points_program : public shader_program {
+public:
+	complex_points_program(GLuint vs, GLuint fs)
+		: shader_program(vs, fs, 0)
+	{
+		/* empty */
+	}
+
+	void set_attribute_locations()
+	{
+		glBindAttribLocation(this->program, 0, "position");
+		glBindAttribLocation(this->program, 1, "vert_color");
+		glBindAttribLocation(this->program, 2, "weight");
+	}
+
+	void get_uniform_locations()
+	{
+		this->vp_uniform =
+			glGetUniformLocation(this->program, "vp");
+		this->m_uniform =
+			glGetUniformLocation(this->program, "m");
+	}
+
+	GLint vp_uniform;
+	GLint m_uniform;
+	GLint weight_uniform;
+};
+
+static complex_points_program *worm_program = 0;
+
+static GLuint timer_queries[1] = { 0, };
+
+static inline
+float degrees_to_radians(float f)
+{
+	return (f * M_PI) / 180.0;
+}
+
+
+class simple_consumer : public GLUshapeConsumer {
+public:
+	simple_consumer(void *_data, unsigned num_verts, uintptr_t base_offset)
+	{
+		GLUvec4 *data = (GLUvec4 *) _data;
+
+		this->position = &data[0 * num_verts];
+		this->position_offset = (uintptr_t) ((char *) this->position
+						     - (char *) _data)
+			+ base_offset;
+
+		this->normal = &data[1 * num_verts];
+		this->normal_offset = (uintptr_t) ((char *) this->normal
+						   - (char *) _data)
+			+ base_offset;
+
+		this->uv = &data[2 * num_verts];
+		this->uv_offset = (uintptr_t) ((char *) this->uv
+					       - (char *) _data)
+			+ base_offset;
+
+		this->tangent = NULL;
+		this->vertex_count = num_verts;
+
+		this->elt = (GLushort *) &data[3 * num_verts];
+		this->elt_offset = (uintptr_t) ((char *) this->elt
+						- (char *) _data)
+			+ base_offset;
+	}
+
+	virtual void begin_primitive(GLenum mode, unsigned count)
+	{
+		this->mode = mode;
+		this->elt_count = count;
+	}
+
+        virtual void index_batch(const unsigned *idx, unsigned count)
+	{
+		for (unsigned i = 0; i < count; i++)
+			this->elt[i] = GLushort(idx[i]);
+
+		this->elt += count;
+	}
+
+	GLushort *elt;
+	uintptr_t elt_offset;
+	unsigned elt_count;
+
+	uintptr_t position_offset;
+	uintptr_t normal_offset;
+	uintptr_t uv_offset;
+
+	GLenum mode;
+};
+
+static inline float frac(float x)
+{
+	return x - floor(x);
+}
+
+class worm_producer : public GLUmeshProducer {
+public:
+	worm_producer(float _length, unsigned _bones)
+		: GLUmeshProducer(5, 9, 9), length(_length), bones(_bones)
+	{
+		/* empty */
+	}
+
+	virtual unsigned
+	vertex_count(void) const
+	{
+		return (this->rows + 1) * this->columns;
+	}
+
+	virtual void
+	generate(GLUshapeConsumer *consumer) const
+	{
+		float data[2 * 8];
+
+		for (unsigned i = 0; i < 8; i++) {
+			const float angle = float(i) * ((2.0 * M_PI) / 8.0);
+			data[(2 * i) + 0] = cos(angle);
+			data[(2 * i) + 1] = sin(angle);
+		}
+		
+		const float step = this->length / float(this->rows);
+		unsigned idx = 0;
+		for (unsigned i = 0; i < (this->rows + 1); i++) {
+			for (unsigned j = 0; j < 8; j++) {
+				consumer->position[idx] =
+					GLUvec4(2.0f * data[(2 * j) + 0],
+						step * float(i),
+						2.0f * data[(2 * j) + 1],
+						1.0f);
+				consumer->normal[idx] =
+					GLUvec4(data[(2 * j) + 0],
+						0.0f,
+						data[(2 * j) + 1],
+						0.0f);
+				consumer->uv[idx] = encode_weight(i);
+
+				idx++;
+			}
+
+			consumer->position[idx] =
+				GLUvec4(2.0f * data[(2 * 0) + 0],
+					step * float(i),
+					2.0f * data[(2 * 0) + 1],
+					1.0f);
+			consumer->normal[idx] =
+				GLUvec4(data[0],
+					0.0f,
+					data[1],
+					0.0f);
+			consumer->uv[idx] = encode_weight(i);
+			idx++;
+		}
+
+		consumer->vertex_batch(consumer->position,
+				       consumer->normal,
+				       consumer->tangent,
+				       consumer->uv,
+				       idx);
+
+		GLUmeshProducer::generate(consumer);
+	}
+
+private:
+	GLUvec4 encode_weight(unsigned i) const
+	{
+		const unsigned n = (this->bones - 1) * i;
+		const unsigned d = (this->rows);
+		const float w = float(n) / float(d);
+		const unsigned b = n / d;
+
+		return GLUvec4(float(b),
+			       float(b + 1),
+			       1.0 - frac(w),
+			       0.0f);
+	}
+
+	float length;
+	unsigned bones;
+};
+
+
+static simple_consumer *worm_sink;
+
+/**
+ * Fill a buffer object with data defining a worm.
+ */
+static simple_consumer *
+fill_in_object_data(GLuint buf)
+{
+	worm_producer worm_source(10.0, 6);
+
+	const unsigned num_verts = worm_source.vertex_count();
+	const unsigned num_elts = worm_source.element_count();
+
+	const unsigned size = (3 * sizeof(GLUvec4) * num_verts)
+		+ (sizeof(GLushort) * num_elts);
+
+	glBindBuffer(GL_ARRAY_BUFFER, buf);
+	glBufferData(GL_ARRAY_BUFFER, size, NULL, GL_STATIC_DRAW);
+	void *ptr = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
+
+	simple_consumer *cons = new simple_consumer(ptr, num_verts, 0);
+	worm_source.generate(cons);
+
+	glUnmapBuffer(GL_ARRAY_BUFFER);
+
+	return cons;
+}
+
+
+static void
+Redisplay(void)
+{
+	static Uint32 last_t = ~0;
+	Uint32 t = SDL_GetTicks();
+
+
+	/* Update animation parameters based on the elaped time.
+	 */
+	if (last_t != (Uint32)~0) {
+		float dt = (float) (t - last_t) / 1000.0f;
+
+		if (anim) {
+			/* Rotate at 60 degrees per second respectively.  All
+			 * of the measurements want angles measured in
+			 * radians.  Do the conversion here.
+			 */
+			y_angle += degrees_to_radians(60.0 * dt);
+		}
+	}
+
+	last_t = t;
+
+	/* Storage for all of the transformation matrices.
+	 */
+	GLUmat4 transformations[6];
+
+	const GLUvec4 eye(eye_distance * cos(0.0),
+			  5.0f,
+			  eye_distance * sin(0.0),
+			  0.0f);
+
+	const GLUmat4 vp(projection_matrix
+			 * gluLookAt(eye,
+				     GLUvec4(-5.0f, 3.0f, 0.0f, 0.0f),
+				     GLUvec4(0.0f, 1.0f, 0.0f, 0.0f)));
+
+	/* Each of the bones rotates the segment by an angle such that the
+	 * combined rotation is pi when the full rotation is used.  Time the
+	 * animation using y_angle to oscillate between -pi and pi with no
+	 * rotation initially.
+	 */
+	const float h = sin(y_angle);
+	const double angle = (h * M_PI) / float(ARRAY_SIZE(transformations) - 2);
+
+	GLUmat4 model(gluIdentityMatrix);
+	transformations[0] = model;
+
+	for (unsigned i = 1; i < (ARRAY_SIZE(transformations) - 1); i++) {
+		/* FINISHME: Generate forward-kinematic transformations for
+		 * FINISHME: each of the bones.
+		 */
+		transformations[i] = model;
+	}
+
+	transformations[5] = transformations[4];
+
+
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+
+	/* Render the worm.
+	 */
+	glUseProgram(worm_program->program);
+
+	if (timer_queries[0])
+		glBeginQuery(GL_TIME_ELAPSED, timer_queries[0]);
+
+	glUniformMatrix4fv(worm_program->vp_uniform, 1, false, (float *) &vp);
+
+	glUniformMatrix4fv(worm_program->m_uniform, ARRAY_SIZE(transformations),
+			   false, (float *) &transformations[0]);
+
+	glDrawElements(worm_sink->mode,
+		       worm_sink->elt_count,
+		       GL_UNSIGNED_SHORT,
+		       BUFFER_OFFSET(worm_sink->elt_offset));
+
+	if (timer_queries[0])
+		glEndQuery(GL_TIME_ELAPSED);
+
+	SDL_GL_SwapBuffers();
+
+	if (timer_queries[0]) {
+		static GLuint64 totals[ARRAY_SIZE(timer_queries)] = { 0, };
+		static unsigned count = 0;
+		GLuint64 result[ARRAY_SIZE(timer_queries)] = { 0, };
+
+		for (unsigned i = 0; i < ARRAY_SIZE(timer_queries); i++) {
+			glGetQueryObjectui64vEXT(timer_queries[i],
+						 GL_QUERY_RESULT,
+						 &result[i]);
+			totals[i] += result[i];
+		}
+
+		count++;
+		if (count > 100) {
+			printf("Timings: %lu\n",
+			       totals[0] / 100);
+
+			memset(totals, 0, sizeof(totals));
+			count = 0;
+		}
+	}
+
+}
+
+static GLuint
+compile_shader_from_file(GLenum target, const char *filename)
+{
+	static const char *const paths_to_try[] = {
+		"",
+		"data/",
+		"../data/",
+		0
+	};
+
+	GLuint shader;
+	char *log = NULL;
+	const char *code;
+
+	const size_t name_len = strlen(filename);
+	for (unsigned i = 0; paths_to_try[i] != 0; i++) {
+		const size_t path_len = strlen(paths_to_try[i]);
+		char *name_with_path = new char [path_len + name_len + 1];
+
+		memcpy(name_with_path, paths_to_try[i], path_len);
+		memcpy(&name_with_path[path_len], filename, name_len);
+		name_with_path[path_len + name_len] = '\0';
+	
+		code = gluLoadTextFile(name_with_path);
+		delete [] name_with_path;
+
+		if (code != NULL)
+			break;
+	}
+
+	if (code == NULL) {
+		fprintf(stderr, "Unable to load shader code for %s.\n",
+			filename);
+		exit(1);
+	}
+
+	shader = gluCompileShader(target, code, &log);
+	if (log != NULL) {
+		printf("Shader compile log for %s:\n%s\n", filename, log);
+		gluReleaseInfoLog(log);
+		log = NULL;
+	}
+
+	if (shader == 0) {
+		fprintf(stderr, "Failed to compile %s.\n", filename);
+		exit(1);
+	}
+
+	gluUnloadTextFile(code);
+
+	return shader;
+}
+
+static complex_points_program *
+create_program(GLuint vs, GLuint fs, const char *name)
+{
+	complex_points_program *p = new complex_points_program(vs, fs);
+
+	p->set_attribute_locations();
+
+	const bool linked = p->link();
+	if (p->log != NULL)
+		printf("%s link log:\n%s\n", name, p->log);
+
+	if (!linked) {
+		fprintf(stderr, "Failed to link %s.\n", name);
+		exit(1);
+	}
+
+	p->get_uniform_locations();
+	return p;
+}
+
+/* Load, compile, link, etc. the vertex and fragment programs.
+ */
+static void
+build_all_shaders(void)
+{
+	gluInitializeCompiler();
+
+	/* If there are dangling instances of these program hanging around,
+	 * clean them up.
+	 */
+	if (worm_program)
+		delete worm_program;
+
+	/* Compile all of the shaders
+	 */
+	GLuint vs = compile_shader_from_file(GL_VERTEX_SHADER,
+					     "simple.vert");
+	GLuint fs = compile_shader_from_file(GL_FRAGMENT_SHADER,
+					     "simple.frag");
+
+	worm_program = create_program(vs, fs, "simple");
+
+	/* The individual shaders have been attached to the programs, so they
+	 * can safely be deleted.
+	 */
+	glDeleteShader(vs);
+	glDeleteShader(fs);
+}
+
+
+static void
+Init(void)
+{
+	glewInit();
+
+	if (!GLEW_VERSION_2_0) {
+		printf ("Sorry, this demo requires OpenGL 2.0 or later.\n");
+		exit(1);
+	}
+
+	if (GLEW_EXT_timer_query || GLEW_ARB_timer_query)
+		glGenQueries(ARRAY_SIZE(timer_queries), timer_queries);
+
+	build_all_shaders();
+
+	glEnable(GL_DEPTH_TEST);
+	glEnable(GL_CULL_FACE);
+
+
+	glGenBuffers(1, & bo);
+	worm_sink = fill_in_object_data(bo);
+
+	glBindBuffer(GL_ARRAY_BUFFER, bo);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, bo);
+
+	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0,
+			      BUFFER_OFFSET(worm_sink->position_offset));
+	glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0,
+			      BUFFER_OFFSET(worm_sink->normal_offset));
+	glVertexAttribPointer(2, 4, GL_FLOAT, GL_FALSE, 0,
+			      BUFFER_OFFSET(worm_sink->uv_offset));
+	glEnableVertexAttribArray(0);
+	glEnableVertexAttribArray(1);
+	glEnableVertexAttribArray(2);
+
+
+	printf("GL_RENDERER = %s\n", (const char *) glGetString(GL_RENDERER));
+	printf("Keyboard input:\n"
+	       "    f: Toggle fullscreen.\n"
+	       "    a: Toggle animation of object.\n"
+	       "    c: Re-load and compile shader program code.\n"
+	       "  ESC: Exit program.\n");
+}
+
+
+static void
+Reshape(int width, int height)
+{
+	my_surf = SDL_SetVideoMode(width, height, 0,
+				   SDL_OPENGL | SDL_RESIZABLE);
+	if (my_surf == NULL) {
+		exit(1);
+	}
+
+	Init();
+
+	const float aspect = float(width) / float(height);
+	gluPerspective4f(& projection_matrix, degrees_to_radians(fov),
+			 aspect, 2.0f, 100.0f);
+	glViewport(0, 0, width, height);
+}
+
+
+static void
+Key(SDLKey sym, bool key_down)
+{
+	if (!key_down)
+		return;
+
+	switch (sym) {
+	case SDLK_ESCAPE:
+		done = true;
+		break;
+
+	case 'f':
+		SDL_WM_ToggleFullScreen(my_surf);
+		break;
+
+		
+	case ' ':
+	case 'a':
+		anim = !anim;
+		break;
+
+	case 'c':
+		printf("Reloading and compiling program code...\n");
+		build_all_shaders();
+		break;
+
+	default:
+		break;
+	}
+}
+
+
+/**
+ * Push an event each time the timer callback fires.
+ */
+Uint32
+timer_callback(Uint32 interval, void *not_used)
+{
+	SDL_Event e;
+
+	(void) not_used;
+
+	e.type = SDL_USEREVENT;
+	e.user.code = 0;
+	e.user.data1 = NULL;
+	e.user.data2 = NULL;
+	SDL_PushEvent(& e);
+
+	return interval;
+}
+
+
+int
+main(int argc, char **argv)
+{
+	(void) argc;
+	(void) argv;
+
+	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) < 0) {
+		exit(1);
+	}
+
+	atexit(SDL_Quit);
+
+	Reshape(800, 600);
+
+	SDL_TimerID timer_id = SDL_AddTimer(10, timer_callback, NULL);
+	t0 = SDL_GetTicks();
+
+	while (!done) {
+		bool draw = false;
+		SDL_Event event;
+
+		SDL_WaitEvent(&event);
+		do {
+			switch (event.type) {
+			case SDL_VIDEORESIZE:
+				Reshape(event.resize.w, event.resize.h);
+				break;
+
+			case SDL_QUIT:
+				done = true;
+				break;
+
+			case SDL_KEYDOWN:
+				Key(event.key.keysym.sym, true);
+				break;
+
+			case SDL_KEYUP:
+				Key(event.key.keysym.sym, false);
+				break;
+
+			case SDL_USEREVENT:
+				draw = true;
+				break;
+
+			default:
+				break;
+			}
+		} while (SDL_PollEvent(&event));
+
+
+		if (draw) {
+			Redisplay();
+		}
+	}
+
+	SDL_RemoveTimer(timer_id);
+
+	SDL_Quit();
+	return 0;
+}