first sketch

1 files changed, 138 insertions, 0 deletions

diff --git a/opengl.c b/opengl.c
new file mode 100644
index 0000000..2b0b70c
--- /dev/null
+++ b/opengl.c
@@ -0,0 +1,138 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <math.h>
+
+#include <GL/freeglut.h>
+
+void draw_axis() {
+	glColor3f(1, 1, 1);
+	glBegin(GL_LINES);
+
+	glVertex2f(0, 0);
+	glVertex2f(1, 0);
+	glVertex2f(0, 0);
+	glVertex2f(0, 1);
+
+	glVertex2f(1, 0);
+	glVertex2f(0.9, 0.1);
+	glVertex2f(1, 0);
+	glVertex2f(0.9, -0.1);
+
+	glVertex2f(0, 1);
+	glVertex2f(0.1, 0.9);
+	glVertex2f(0, 1);
+	glVertex2f(-0.1, 0.9);
+
+	glEnd();
+}
+
+void draw_grid() {
+	glColor3f(0.2, 0.2, 0.2);
+
+	glBegin(GL_LINES);
+
+	for (int i = -10; i < 10; ++i) {
+		glVertex2f(i, -10);
+		glVertex2f(i, 10);
+	}
+
+	for (int i = -10; i < 10; ++i) {
+		glVertex2f(-10, i);
+		glVertex2f(10, i);
+	}
+
+	glEnd();
+
+	glColor3f(0.5, 0.5, 0.5);
+
+	glBegin(GL_LINES);
+
+	glVertex2f(-10, 0);
+	glVertex2f(10, 0);
+
+	glVertex2f(0, -10);
+	glVertex2f(0, 10);
+
+	glEnd();
+}
+
+void draw_function(double from, double to, double step, double(*fun)(double)) {
+	glColor3f(0.9f, 0.5f, 0.2f);
+	glLineWidth(2);
+	glBegin(GL_LINES);
+
+	for (float i = from; i < to; i += step) {
+		double current = fun(i);
+		double next = fun(i + step);
+
+		glVertex2f(i, current);
+		glVertex2f(i + step, next);
+	}
+
+	glEnd();
+}
+
+double tp(double x, double a, double b, double c, double d) {
+	return a * x * x * x + b * x * x + c * x + d;
+}
+
+double example_function(double x) {
+	return tp(x, 1, 5, 5, -1);
+}
+
+static void display(void) {
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+
+	draw_grid();
+	draw_axis();
+	draw_function(-10, 10, 0.01, &example_function);
+
+	glutSwapBuffers();
+}
+
+static void keyboard(unsigned char key, int x, int y) {
+	printf("Pressed %c key\n", key);
+	if(key == 'q') {
+		exit(0);
+	}
+}
+
+void enableMultisample(int msaa) {
+	if (msaa) {
+		glEnable(GL_MULTISAMPLE);
+		glHint(GL_MULTISAMPLE_FILTER_HINT_NV, GL_NICEST);
+
+		// detect current settings
+		GLint iMultiSample = 0;
+		GLint iNumSamples = 0;
+		glGetIntegerv(GL_SAMPLE_BUFFERS, &iMultiSample);
+		glGetIntegerv(GL_SAMPLES, &iNumSamples);
+		printf("MSAA on, GL_SAMPLE_BUFFERS = %d, GL_SAMPLES = %d\n", iMultiSample, iNumSamples);
+	} else {
+		glDisable(GL_MULTISAMPLE);
+		printf("MSAA off\n");
+	}   
+}
+
+int main(int argc, char **argv) {
+	glutInit(&argc, argv);
+	glutInitWindowSize(600, 600);
+	glutSetOption(GLUT_MULTISAMPLE, 8);
+	glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
+	glutCreateWindow("cme");
+
+	enableMultisample(1);
+
+	printf("OpenGL version = %s\n", glGetString(GL_VERSION));
+
+	glutDisplayFunc(display);
+	glutKeyboardFunc(keyboard);
+
+	glScalef(0.1, 0.1, 0.1);
+	glClearColor(0.0, 0.0, 0.0, 1.0);
+
+
+	glutMainLoop();
+}