| /* |
| * Copyright (C) 1999-2001 Brian Paul All Rights Reserved. |
| * |
| * 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 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 |
| * BRIAN PAUL 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. |
| */ |
| |
| /* |
| * Ported to GLES2. |
| * Kristian Høgsberg <krh@bitplanet.net> |
| * May 3, 2010 |
| * |
| * Improve GLES2 port: |
| * * Refactor gear drawing. |
| * * Use correct normals for surfaces. |
| * * Improve shader. |
| * * Use perspective projection transformation. |
| * * Add FPS count. |
| * * Add comments. |
| * Alexandros Frantzis <alexandros.frantzis@linaro.org> |
| * Jul 13, 2010 |
| */ |
| |
| /* |
| * Port to Mendel Linux Wayland by Peter Nordström 1 June 2020 |
| * |
| * Window handling and egl initialization done externally in |
| * simple-egl.c |
| */ |
| |
| |
| #define _GNU_SOURCE |
| |
| #include <GLES2/gl2.h> |
| #include <math.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| |
| extern void HandleFrame(void); |
| |
| #define STRIPS_PER_TOOTH 7 |
| #define VERTICES_PER_TOOTH 34 |
| #define GEAR_VERTEX_STRIDE 6 |
| |
| /** |
| * Struct describing the vertices in triangle strip |
| */ |
| struct vertex_strip { |
| /** The first vertex in the strip */ |
| GLint first; |
| /** The number of consecutive vertices in the strip after the first */ |
| GLint count; |
| }; |
| |
| /* Each vertex consist of GEAR_VERTEX_STRIDE GLfloat attributes */ |
| typedef GLfloat GearVertex[GEAR_VERTEX_STRIDE]; |
| |
| /** |
| * Struct representing a gear. |
| */ |
| struct gear { |
| /** The array of vertices comprising the gear */ |
| GearVertex *vertices; |
| /** The number of vertices comprising the gear */ |
| int nvertices; |
| /** The array of triangle strips comprising the gear */ |
| struct vertex_strip *strips; |
| /** The number of triangle strips comprising the gear */ |
| int nstrips; |
| /** The Vertex Buffer Object holding the vertices in the graphics card */ |
| GLuint vbo; |
| }; |
| |
| /** The view rotation [x, y, z] */ |
| static GLfloat view_rot[3] = { 20.0, 30.0, 0.0 }; |
| /** The gears */ |
| static struct gear *gear1, *gear2, *gear3; |
| /** The current gear rotation angle */ |
| static GLfloat angle = 0.0; |
| /** The location of the shader uniforms */ |
| static GLuint ModelViewProjectionMatrix_location, |
| NormalMatrix_location, |
| LightSourcePosition_location, |
| MaterialColor_location; |
| /** The projection matrix */ |
| static GLfloat ProjectionMatrix[16]; |
| /** The direction of the directional light for the scene */ |
| static const GLfloat LightSourcePosition[4] = { 5.0, 5.0, 10.0, 1.0}; |
| |
| /** |
| * Fills a gear vertex. |
| * |
| * @param v the vertex to fill |
| * @param x the x coordinate |
| * @param y the y coordinate |
| * @param z the z coortinate |
| * @param n pointer to the normal table |
| * |
| * @return the operation error code |
| */ |
| static GearVertex * |
| vert(GearVertex *v, GLfloat x, GLfloat y, GLfloat z, GLfloat n[3]) |
| { |
| v[0][0] = x; |
| v[0][1] = y; |
| v[0][2] = z; |
| v[0][3] = n[0]; |
| v[0][4] = n[1]; |
| v[0][5] = n[2]; |
| |
| return v + 1; |
| } |
| |
| /** |
| * Create a gear wheel. |
| * |
| * @param inner_radius radius of hole at center |
| * @param outer_radius radius at center of teeth |
| * @param width width of gear |
| * @param teeth number of teeth |
| * @param tooth_depth depth of tooth |
| * |
| * @return pointer to the constructed struct gear |
| */ |
| static struct gear * |
| create_gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width, |
| GLint teeth, GLfloat tooth_depth) |
| { |
| GLfloat r0, r1, r2; |
| GLfloat da; |
| GearVertex *v; |
| struct gear *gear; |
| double s[5], c[5]; |
| GLfloat normal[3]; |
| int cur_strip = 0; |
| int i; |
| |
| /* Allocate memory for the gear */ |
| gear = malloc(sizeof *gear); |
| if (gear == NULL) |
| return NULL; |
| |
| /* Calculate the radii used in the gear */ |
| r0 = inner_radius; |
| r1 = outer_radius - tooth_depth / 2.0; |
| r2 = outer_radius + tooth_depth / 2.0; |
| |
| da = 2.0 * M_PI / teeth / 4.0; |
| |
| /* Allocate memory for the triangle strip information */ |
| gear->nstrips = STRIPS_PER_TOOTH * teeth; |
| gear->strips = calloc(gear->nstrips, sizeof (*gear->strips)); |
| |
| /* Allocate memory for the vertices */ |
| gear->vertices = calloc(VERTICES_PER_TOOTH * teeth, sizeof(*gear->vertices)); |
| v = gear->vertices; |
| |
| for (i = 0; i < teeth; i++) { |
| /* Calculate needed sin/cos for varius angles */ |
| sincos(i * 2.0 * M_PI / teeth, &s[0], &c[0]); |
| sincos(i * 2.0 * M_PI / teeth + da, &s[1], &c[1]); |
| sincos(i * 2.0 * M_PI / teeth + da * 2, &s[2], &c[2]); |
| sincos(i * 2.0 * M_PI / teeth + da * 3, &s[3], &c[3]); |
| sincos(i * 2.0 * M_PI / teeth + da * 4, &s[4], &c[4]); |
| |
| /* A set of macros for making the creation of the gears easier */ |
| #define GEAR_POINT(r, da) { (r) * c[(da)], (r) * s[(da)] } |
| #define SET_NORMAL(x, y, z) do { \ |
| normal[0] = (x); normal[1] = (y); normal[2] = (z); \ |
| } while(0) |
| |
| #define GEAR_VERT(v, point, sign) vert((v), p[(point)].x, p[(point)].y, (sign) * width * 0.5, normal) |
| |
| #define START_STRIP do { \ |
| gear->strips[cur_strip].first = v - gear->vertices; \ |
| } while(0); |
| |
| #define END_STRIP do { \ |
| int _tmp = (v - gear->vertices); \ |
| gear->strips[cur_strip].count = _tmp - gear->strips[cur_strip].first; \ |
| cur_strip++; \ |
| } while (0) |
| |
| #define QUAD_WITH_NORMAL(p1, p2) do { \ |
| SET_NORMAL((p[(p1)].y - p[(p2)].y), -(p[(p1)].x - p[(p2)].x), 0); \ |
| v = GEAR_VERT(v, (p1), -1); \ |
| v = GEAR_VERT(v, (p1), 1); \ |
| v = GEAR_VERT(v, (p2), -1); \ |
| v = GEAR_VERT(v, (p2), 1); \ |
| } while(0) |
| |
| struct point { |
| GLfloat x; |
| GLfloat y; |
| }; |
| |
| /* Create the 7 points (only x,y coords) used to draw a tooth */ |
| struct point p[7] = { |
| GEAR_POINT(r2, 1), // 0 |
| GEAR_POINT(r2, 2), // 1 |
| GEAR_POINT(r1, 0), // 2 |
| GEAR_POINT(r1, 3), // 3 |
| GEAR_POINT(r0, 0), // 4 |
| GEAR_POINT(r1, 4), // 5 |
| GEAR_POINT(r0, 4), // 6 |
| }; |
| |
| /* Front face */ |
| START_STRIP; |
| SET_NORMAL(0, 0, 1.0); |
| v = GEAR_VERT(v, 0, +1); |
| v = GEAR_VERT(v, 1, +1); |
| v = GEAR_VERT(v, 2, +1); |
| v = GEAR_VERT(v, 3, +1); |
| v = GEAR_VERT(v, 4, +1); |
| v = GEAR_VERT(v, 5, +1); |
| v = GEAR_VERT(v, 6, +1); |
| END_STRIP; |
| |
| /* Inner face */ |
| START_STRIP; |
| QUAD_WITH_NORMAL(4, 6); |
| END_STRIP; |
| |
| /* Back face */ |
| START_STRIP; |
| SET_NORMAL(0, 0, -1.0); |
| v = GEAR_VERT(v, 6, -1); |
| v = GEAR_VERT(v, 5, -1); |
| v = GEAR_VERT(v, 4, -1); |
| v = GEAR_VERT(v, 3, -1); |
| v = GEAR_VERT(v, 2, -1); |
| v = GEAR_VERT(v, 1, -1); |
| v = GEAR_VERT(v, 0, -1); |
| END_STRIP; |
| |
| /* Outer face */ |
| START_STRIP; |
| QUAD_WITH_NORMAL(0, 2); |
| END_STRIP; |
| |
| START_STRIP; |
| QUAD_WITH_NORMAL(1, 0); |
| END_STRIP; |
| |
| START_STRIP; |
| QUAD_WITH_NORMAL(3, 1); |
| END_STRIP; |
| |
| START_STRIP; |
| QUAD_WITH_NORMAL(5, 3); |
| END_STRIP; |
| } |
| |
| gear->nvertices = (v - gear->vertices); |
| |
| /* Store the vertices in a vertex buffer object (VBO) */ |
| glGenBuffers(1, &gear->vbo); |
| glBindBuffer(GL_ARRAY_BUFFER, gear->vbo); |
| glBufferData(GL_ARRAY_BUFFER, gear->nvertices * sizeof(GearVertex), |
| gear->vertices, GL_STATIC_DRAW); |
| |
| return gear; |
| } |
| |
| /** |
| * Multiplies two 4x4 matrices. |
| * |
| * The result is stored in matrix m. |
| * |
| * @param m the first matrix to multiply |
| * @param n the second matrix to multiply |
| */ |
| static void |
| multiply(GLfloat *m, const GLfloat *n) |
| { |
| GLfloat tmp[16]; |
| const GLfloat *row, *column; |
| div_t d; |
| int i, j; |
| |
| for (i = 0; i < 16; i++) { |
| tmp[i] = 0; |
| d = div(i, 4); |
| row = n + d.quot * 4; |
| column = m + d.rem; |
| for (j = 0; j < 4; j++) |
| tmp[i] += row[j] * column[j * 4]; |
| } |
| memcpy(m, &tmp, sizeof tmp); |
| } |
| |
| /** |
| * Rotates a 4x4 matrix. |
| * |
| * @param[in,out] m the matrix to rotate |
| * @param angle the angle to rotate |
| * @param x the x component of the direction to rotate to |
| * @param y the y component of the direction to rotate to |
| * @param z the z component of the direction to rotate to |
| */ |
| static void |
| rotate(GLfloat *m, GLfloat angle, GLfloat x, GLfloat y, GLfloat z) |
| { |
| double s, c; |
| |
| sincos(angle, &s, &c); |
| GLfloat r[16] = { |
| x * x * (1 - c) + c, y * x * (1 - c) + z * s, x * z * (1 - c) - y * s, 0, |
| x * y * (1 - c) - z * s, y * y * (1 - c) + c, y * z * (1 - c) + x * s, 0, |
| x * z * (1 - c) + y * s, y * z * (1 - c) - x * s, z * z * (1 - c) + c, 0, |
| 0, 0, 0, 1 |
| }; |
| |
| multiply(m, r); |
| } |
| |
| |
| /** |
| * Translates a 4x4 matrix. |
| * |
| * @param[in,out] m the matrix to translate |
| * @param x the x component of the direction to translate to |
| * @param y the y component of the direction to translate to |
| * @param z the z component of the direction to translate to |
| */ |
| static void |
| translate(GLfloat *m, GLfloat x, GLfloat y, GLfloat z) |
| { |
| GLfloat t[16] = { 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, x, y, z, 1 }; |
| |
| multiply(m, t); |
| } |
| |
| /** |
| * Creates an identity 4x4 matrix. |
| * |
| * @param m the matrix make an identity matrix |
| */ |
| static void |
| identity(GLfloat *m) |
| { |
| GLfloat t[16] = { |
| 1.0, 0.0, 0.0, 0.0, |
| 0.0, 1.0, 0.0, 0.0, |
| 0.0, 0.0, 1.0, 0.0, |
| 0.0, 0.0, 0.0, 1.0, |
| }; |
| |
| memcpy(m, t, sizeof(t)); |
| } |
| |
| /** |
| * Transposes a 4x4 matrix. |
| * |
| * @param m the matrix to transpose |
| */ |
| static void |
| transpose(GLfloat *m) |
| { |
| GLfloat t[16] = { |
| m[0], m[4], m[8], m[12], |
| m[1], m[5], m[9], m[13], |
| m[2], m[6], m[10], m[14], |
| m[3], m[7], m[11], m[15]}; |
| |
| memcpy(m, t, sizeof(t)); |
| } |
| |
| /** |
| * Inverts a 4x4 matrix. |
| * |
| * This function can currently handle only pure translation-rotation matrices. |
| * Read http://www.gamedev.net/community/forums/topic.asp?topic_id=425118 |
| * for an explanation. |
| */ |
| static void |
| invert(GLfloat *m) |
| { |
| GLfloat t[16]; |
| identity(t); |
| |
| // Extract and invert the translation part 't'. The inverse of a |
| // translation matrix can be calculated by negating the translation |
| // coordinates. |
| t[12] = -m[12]; t[13] = -m[13]; t[14] = -m[14]; |
| |
| // Invert the rotation part 'r'. The inverse of a rotation matrix is |
| // equal to its transpose. |
| m[12] = m[13] = m[14] = 0; |
| transpose(m); |
| |
| // inv(m) = inv(r) * inv(t) |
| multiply(m, t); |
| } |
| |
| /** |
| * Calculate a perspective projection transformation. |
| * |
| * @param m the matrix to save the transformation in |
| * @param fovy the field of view in the y direction |
| * @param aspect the view aspect ratio |
| * @param zNear the near clipping plane |
| * @param zFar the far clipping plane |
| */ |
| void perspective(GLfloat *m, GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar) |
| { |
| GLfloat tmp[16]; |
| identity(tmp); |
| |
| double sine, cosine, cotangent, deltaZ; |
| GLfloat radians = fovy / 2 * M_PI / 180; |
| |
| deltaZ = zFar - zNear; |
| sincos(radians, &sine, &cosine); |
| |
| if ((deltaZ == 0) || (sine == 0) || (aspect == 0)) |
| return; |
| |
| cotangent = cosine / sine; |
| |
| tmp[0] = cotangent / aspect; |
| tmp[5] = cotangent; |
| tmp[10] = -(zFar + zNear) / deltaZ; |
| tmp[11] = -1; |
| tmp[14] = -2 * zNear * zFar / deltaZ; |
| tmp[15] = 0; |
| |
| memcpy(m, tmp, sizeof(tmp)); |
| } |
| |
| /** |
| * Draws a gear. |
| * |
| * @param gear the gear to draw |
| * @param transform the current transformation matrix |
| * @param x the x position to draw the gear at |
| * @param y the y position to draw the gear at |
| * @param angle the rotation angle of the gear |
| * @param color the color of the gear |
| */ |
| static void |
| draw_gear(struct gear *gear, GLfloat *transform, |
| GLfloat x, GLfloat y, GLfloat angle, const GLfloat color[4]) |
| { |
| GLfloat model_view[16]; |
| GLfloat normal_matrix[16]; |
| GLfloat model_view_projection[16]; |
| |
| /* Translate and rotate the gear */ |
| memcpy(model_view, transform, sizeof (model_view)); |
| translate(model_view, x, y, 0); |
| rotate(model_view, 2 * M_PI * angle / 360.0, 0, 0, 1); |
| |
| /* Create and set the ModelViewProjectionMatrix */ |
| memcpy(model_view_projection, ProjectionMatrix, sizeof(model_view_projection)); |
| multiply(model_view_projection, model_view); |
| |
| glUniformMatrix4fv(ModelViewProjectionMatrix_location, 1, GL_FALSE, |
| model_view_projection); |
| |
| /* |
| * Create and set the NormalMatrix. It's the inverse transpose of the |
| * ModelView matrix. |
| */ |
| memcpy(normal_matrix, model_view, sizeof (normal_matrix)); |
| invert(normal_matrix); |
| transpose(normal_matrix); |
| glUniformMatrix4fv(NormalMatrix_location, 1, GL_FALSE, normal_matrix); |
| |
| /* Set the gear color */ |
| glUniform4fv(MaterialColor_location, 1, color); |
| |
| /* Set the vertex buffer object to use */ |
| glBindBuffer(GL_ARRAY_BUFFER, gear->vbo); |
| |
| /* Set up the position of the attributes in the vertex buffer object */ |
| glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, |
| 6 * sizeof(GLfloat), NULL); |
| glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, |
| 6 * sizeof(GLfloat), (GLfloat *) 0 + 3); |
| |
| /* Enable the attributes */ |
| glEnableVertexAttribArray(0); |
| glEnableVertexAttribArray(1); |
| |
| /* Draw the triangle strips that comprise the gear */ |
| int n; |
| for (n = 0; n < gear->nstrips; n++) |
| glDrawArrays(GL_TRIANGLE_STRIP, gear->strips[n].first, gear->strips[n].count); |
| |
| /* Disable the attributes */ |
| glDisableVertexAttribArray(1); |
| glDisableVertexAttribArray(0); |
| } |
| |
| /** |
| * Draws the gears. |
| */ |
| static void |
| gears_draw(void) |
| { |
| const static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 }; |
| const static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 }; |
| const static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 }; |
| GLfloat transform[16]; |
| identity(transform); |
| |
| glClearColor(0.0, 0.0, 0.0, 0.0); |
| glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); |
| |
| /* Translate and rotate the view */ |
| translate(transform, 0, 0, -20); |
| rotate(transform, 2 * M_PI * view_rot[0] / 360.0, 1, 0, 0); |
| rotate(transform, 2 * M_PI * view_rot[1] / 360.0, 0, 1, 0); |
| rotate(transform, 2 * M_PI * view_rot[2] / 360.0, 0, 0, 1); |
| |
| /* Draw the gears */ |
| draw_gear(gear1, transform, -3.0, -2.0, angle, red); |
| draw_gear(gear2, transform, 3.1, -2.0, -2 * angle - 9.0, green); |
| draw_gear(gear3, transform, -3.1, 4.2, -2 * angle - 25.0, blue); |
| } |
| |
| /** |
| * Handles a new window size or exposure. |
| * |
| * @param width the window width |
| * @param height the window height |
| */ |
| static void |
| gears_reshape(int width, int height) |
| { |
| /* Update the projection matrix */ |
| perspective(ProjectionMatrix, 60.0, width / (float)height, 1.0, 1024.0); |
| |
| /* Set the viewport */ |
| glViewport(0, 0, (GLint) width, (GLint) height); |
| } |
| |
| static const char vertex_shader[] = |
| "attribute vec3 position;\n" |
| "attribute vec3 normal;\n" |
| "\n" |
| "uniform mat4 ModelViewProjectionMatrix;\n" |
| "uniform mat4 NormalMatrix;\n" |
| "uniform vec4 LightSourcePosition;\n" |
| "uniform vec4 MaterialColor;\n" |
| "\n" |
| "varying vec4 Color;\n" |
| "\n" |
| "void main(void)\n" |
| "{\n" |
| " // Transform the normal to eye coordinates\n" |
| " vec3 N = normalize(vec3(NormalMatrix * vec4(normal, 1.0)));\n" |
| "\n" |
| " // The LightSourcePosition is actually its direction for directional light\n" |
| " vec3 L = normalize(LightSourcePosition.xyz);\n" |
| "\n" |
| " // Multiply the diffuse value by the vertex color (which is fixed in this case)\n" |
| " // to get the actual color that we will use to draw this vertex with\n" |
| " float diffuse = max(dot(N, L), 0.0);\n" |
| " Color = diffuse * MaterialColor;\n" |
| "\n" |
| " // Transform the position to clip coordinates\n" |
| " gl_Position = ModelViewProjectionMatrix * vec4(position, 1.0);\n" |
| "}"; |
| |
| static const char fragment_shader[] = |
| "precision mediump float;\n" |
| "varying vec4 Color;\n" |
| "\n" |
| "void main(void)\n" |
| "{\n" |
| " gl_FragColor = Color;\n" |
| "}"; |
| |
| static void |
| gears_init(void) |
| { |
| GLuint v, f, program; |
| const char *p; |
| char msg[512]; |
| |
| glEnable(GL_CULL_FACE); |
| glEnable(GL_DEPTH_TEST); |
| |
| /* Compile the vertex shader */ |
| p = vertex_shader; |
| v = glCreateShader(GL_VERTEX_SHADER); |
| glShaderSource(v, 1, &p, NULL); |
| glCompileShader(v); |
| glGetShaderInfoLog(v, sizeof msg, NULL, msg); |
| |
| /* Compile the fragment shader */ |
| p = fragment_shader; |
| f = glCreateShader(GL_FRAGMENT_SHADER); |
| glShaderSource(f, 1, &p, NULL); |
| glCompileShader(f); |
| glGetShaderInfoLog(f, sizeof msg, NULL, msg); |
| |
| /* Create and link the shader program */ |
| program = glCreateProgram(); |
| glAttachShader(program, v); |
| glAttachShader(program, f); |
| glBindAttribLocation(program, 0, "position"); |
| glBindAttribLocation(program, 1, "normal"); |
| |
| glLinkProgram(program); |
| glGetProgramInfoLog(program, sizeof msg, NULL, msg); |
| |
| /* Enable the shaders */ |
| glUseProgram(program); |
| |
| /* Get the locations of the uniforms so we can access them */ |
| ModelViewProjectionMatrix_location = glGetUniformLocation(program, "ModelViewProjectionMatrix"); |
| NormalMatrix_location = glGetUniformLocation(program, "NormalMatrix"); |
| LightSourcePosition_location = glGetUniformLocation(program, "LightSourcePosition"); |
| MaterialColor_location = glGetUniformLocation(program, "MaterialColor"); |
| |
| /* Set the LightSourcePosition uniform which is constant throught the program */ |
| glUniform4fv(LightSourcePosition_location, 1, LightSourcePosition); |
| |
| /* make the gears */ |
| gear1 = create_gear(1.0, 4.0, 1.0, 20, 0.7); |
| gear2 = create_gear(0.5, 2.0, 2.0, 10, 0.7); |
| gear3 = create_gear(1.3, 2.0, 0.5, 10, 0.7); |
| } |
| |
| void RunGears() { |
| gears_init(); |
| gears_reshape(600, 600); |
| while (1) { |
| double dt = 0.01666; |
| |
| /* advance rotation for next frame */ |
| angle += 70.0 * dt; /* 70 degrees per second */ |
| if (angle > 3600.0) |
| angle -= 3600.0; |
| |
| gears_draw(); |
| HandleFrame(); |
| } |
| } |