commit ad95809dbab825b09804b2a1ceceb1ad09ba0e3d
parent c2aa6601fedb944bfdbfef3d356626cafe9db466
Author: bsandro <email@bsandro.tech>
Date: Sun, 19 Oct 2025 14:13:09 +0300
tesselation
Diffstat:
| M | main2.c | | | 130 | ++++++++++++++++++++++++++++++++++++++++++++++++++++---------------------------- |
1 file changed, 85 insertions(+), 45 deletions(-)
diff --git a/main2.c b/main2.c
@@ -12,7 +12,9 @@
#include <GL/glx.h>
#include <GL/glu.h>
-static const GLint attr[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
+#ifndef CALLBACK
+#define CALLBACK void (*)(void)
+#endif
static const double current_ts() {
struct timespec ts;
@@ -22,6 +24,41 @@ static const double current_ts() {
static double t_started;
+static void tessCbBegin(GLenum type) {
+ glBegin(type);
+ printf("glBegin(%d)\n", type);
+}
+
+static void tessCbVertex(void *data) {
+ const float scale = 0.2f;
+ const GLdouble *p = data;
+ glVertex3d(p[0]*scale, p[1]*scale, p[2]);
+ printf("glVertex3d(%.1f, %.1f, %.1f)\n", *p, *(p+1), *(p+2));
+}
+
+static void tessCbEnd() {
+ glEnd();
+ printf("glEnd()\n");
+}
+
+static void tessCbError(GLenum errno) {
+ printf("tesselator error: %d\n", errno);
+}
+
+static void tessCbCombine(GLdouble coords[3], GLdouble *data[4], GLfloat weight[4], void **outData) {
+ // let memory leak for now
+ GLdouble *out = malloc(sizeof(GLdouble)*7); // x,y,z,r,g,b,a
+ out[0] = coords[0];
+ out[1] = coords[1];
+ out[2] = coords[2];
+ // color
+ out[3] = weight[0]*data[0][3]+weight[1]*data[1][3]+weight[2]*data[2][3]+weight[3]*data[3][3];
+ out[4] = weight[0]*data[0][4]+weight[1]*data[1][4]+weight[2]*data[2][4]+weight[3]*data[3][4];
+ out[5] = weight[0]*data[0][5]+weight[1]*data[1][5]+weight[2]*data[2][5]+weight[3]*data[3][5];
+ out[6] = weight[0]*data[0][6]+weight[1]*data[1][6]+weight[2]*data[2][6]+weight[3]*data[3][6];
+ *outData = out;
+}
+
//@todo move shaders to separate files
static const GLchar *vertexSrc = " \n\
#version 420 \n\
@@ -85,7 +122,7 @@ int main(int argc, char *argv[]) {
Window win;
XWindowAttributes gwa;
XEvent xev;
-
+ GLint attr[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
if (dpy == NULL) {
printf("\n\tcannot connect to X server\n\n");
@@ -111,42 +148,29 @@ int main(int argc, char *argv[]) {
GLXContext ctx = glXCreateContext(dpy, vi, NULL, GL_TRUE);
glXMakeCurrent(dpy, win, ctx);
- GLuint vao;
- glGenVertexArrays(1, &vao);
- glBindVertexArray(vao);
-
- // [x, y, r, g, b]
- static const GLfloat vertices[] = {
- 0.01f, 0.01f, 1.0f, 0.0f, 0.0f,
- 0.8f, 0.0f, 0.0f, 1.0f, 0.0f,
- 0.0f, 0.8f, 0.0f, 0.0f, 1.0f,
-
- -0.01f, -0.01f, 0.0f, 0.0f, 1.0f,
- -0.8f, 0.0f, 0.0f, 1.0f, 0.0f,
- 0.0f, -0.8f, 1.0f, 0.0f, 0.0f,
-
- 0.3f, 0.3f, 1.0f, 0.0f, 0.0f,
- 0.3f, 0.6f, 1.0f, 0.0f, 0.0f,
- 0.6f, 0.3f, 1.0f, 0.0f, 0.0f,
- 0.6f, 0.6f, 1.0f, 0.0f, 0.0f
- };
-
- static const GLuint elements[] = {
- 0, 1, 5,
- 3, 2, 4,
- 6, 7, 8,
- 7, 8, 9
- };
-
- GLuint vbo;
- glGenBuffers(1, &vbo);
- glBindBuffer(GL_ARRAY_BUFFER, vbo);
- glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
-
- GLuint ebo;
- glGenBuffers(1, &ebo);
- glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
- glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);
+ //GLdouble vertices_poly[][3] = { {-2,3,0}, {-2,0,0}, {2,0,0}, { 2,3,0}, {-1,2,0}, {-1,1,0}, {1,1,0}, { 1,2,0} };
+ //GLdouble vertices_poly[][3] = { {-0.5,0.9,0}, {0,-0.5,0}, {0.5,0.9,0}, {0,0.3,0} };
+ /*GLdouble vertices_poly[][3] = {
+ { -0.7, -0.5, 0.0 },
+ { -0.3, 0.3, 0.0 },
+ { 0.0, 0.6, 0.0 },
+ { 0.4, 0.3, 0.0 },
+ { 0.2, -0.4, 0.0 },
+ { 0.7, -0.4, 0.0 },
+ { -0.4, -0.7, 0.0 }
+ };*/
+ GLdouble vertices_poly[][6] = { { 0.0, 3.0, 0, 1, 0, 0},
+ {-1.0, 0.0, 0, 0, 1, 0},
+ { 1.6, 1.9, 0, 1, 0, 1},
+ {-1.6, 1.9, 0, 1, 1, 0},
+ { 1.0, 0.0, 0, 0, 0, 1} };
+ int vertices_num = sizeof(vertices_poly)/sizeof(vertices_poly[0]);
+ GLUtesselator *tess = gluNewTess();
+ gluTessCallback(tess, GLU_TESS_BEGIN, (CALLBACK)tessCbBegin);
+ gluTessCallback(tess, GLU_TESS_END, (CALLBACK)tessCbEnd);
+ gluTessCallback(tess, GLU_TESS_VERTEX, (CALLBACK)tessCbVertex);
+ gluTessCallback(tess, GLU_TESS_ERROR, (CALLBACK)tessCbError);
+ gluTessCallback(tess, GLU_TESS_COMBINE, (CALLBACK)tessCbCombine);
GLuint vertex = mkShader(GL_VERTEX_SHADER, vertexSrc);
GLuint fragment = mkShader(GL_FRAGMENT_SHADER, fragmentSrc);
@@ -174,6 +198,17 @@ int main(int argc, char *argv[]) {
}
}
+ // doesn't work for tesselation
+ /*glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(-10, 10, -10, 10, -1.5, 1.5);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();*/
+
+ //glMatrixMode(GL_MODELVIEW);
+ //glLoadIdentity();
+ //glScaled(0.1, 0.1, 1.0);
+
glClearColor(0.1f, 0.1f, 0.15f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
@@ -183,13 +218,18 @@ int main(int argc, char *argv[]) {
glUseProgram(shaderPrg);
- GLint position = glGetAttribLocation(shaderPrg, "position");
- glEnableVertexAttribArray(position);
- glVertexAttribPointer(position, 2, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), 0);
- GLint color = glGetAttribLocation(shaderPrg, "inColor");
- glEnableVertexAttribArray(color);
- glVertexAttribPointer(color, 3, GL_FLOAT, GL_FALSE, 5*sizeof(GLfloat), (void *)(2*sizeof(GLfloat)));
- glDrawElements(GL_TRIANGLES, sizeof(elements), GL_UNSIGNED_INT, 0);
+ GLuint list = glGenLists(1);
+ glNewList(list, GL_COMPILE);
+ gluTessBeginPolygon(tess, NULL);
+ gluTessBeginContour(tess);
+ for (int i=0;i<vertices_num;++i) {
+ gluTessVertex(tess, vertices_poly[i], vertices_poly[i]);
+ }
+ gluTessEndContour(tess);
+ gluTessEndPolygon(tess);
+ glEndList();
+
+ glCallList(list);
glXSwapBuffers(dpy, win);
usleep(1000*16);
