From ac1ed354ce44bbc25392e871e2cede8385922f9e Mon Sep 17 00:00:00 2001
From: Rusty Striker <avivr903@tutanota.com>
Date: Thu, 6 Jul 2023 13:11:08 +0300
Subject: [PATCH] camera movement(wip)

---
 mmn_17.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 52 insertions(+), 9 deletions(-)

diff --git a/mmn_17.c b/mmn_17.c
index 4bdec15..b7413e2 100644
--- a/mmn_17.c
+++ b/mmn_17.c
@@ -6,11 +6,19 @@
 #include <stdio.h>
 #include <math.h>
 #include "ui.h"
+// close enough
+#define PI 3.14
 
-int lastMouseButton = GLUT_LEFT_BUTTON;
-ui_slider* draggedSlider = NULL;
+
+// Camera rotation and stuff
+float camRadius = 10.0;
+vec3 camCenter = { 0.0, 0.0, 0.0 };
+vec3 camRot = { PI * 0.125, 0.0, 0.0 };
 
 // Ui stuff
+int lastMouseButton = GLUT_LEFT_BUTTON;
+int lastMouseX = 0, lastMouseY = 0;
+ui_slider* draggedSlider = NULL;
 void testButtonClick();
 ui_button buttons[] = {
     { 
@@ -24,7 +32,7 @@ ui_button buttons[] = {
 ui_slider sliders[] = {
     {
         /* pos */ { { 0.5, 0.7, 0.0 }, {-50.0, -5.0, 0.0 } },
-        /* size */ { 100.0, 10.0, 10.0 },
+        /* size */ { 100.0, 10.0, 8.0 },
         0.1
     }
 };
@@ -32,6 +40,7 @@ ui_slider sliders[] = {
 void testButtonClick() {
     printf("Clicked!\n");
     sliders[0].value = 0.5;
+    camCenter = vec3_new(0.0, 1.0, 0.0);
     glutPostRedisplay();
 }
 
@@ -65,15 +74,27 @@ void drawWorld(void) {
     // set perspective camera
     GLdouble wWidth = (GLdouble) glutGet(GLUT_WINDOW_WIDTH);
     GLdouble wHeight = (GLdouble) glutGet(GLUT_WINDOW_HEIGHT);
+    // Calculate current camera position from rotation
+    vec3 cp = vec3_new(0.0, 0.0, 0.0);
+    // rotate along the x axis(yz plane)
+    cp.z = cosf(camRot.x);
+    cp.y = sinf(camRot.x);
+    // rotate along the y axis(xy plane)
+    cp.x = cp.z * sinf(camRot.y);
+    cp.z *= cosf(camRot.y);
+    cp = vec3_mult(cp, camRadius);
+    cp = vec3_add(cp, camCenter);
+    
     glMatrixMode(GL_MODELVIEW);
     glLoadIdentity();
-    gluLookAt(0.0, 10.0, 20.0, (0.5 - sliders[0].value) * 10.0, 0.0, 0.0, 0.0, 1.0, 0.0);
+    gluLookAt(cp.x, cp.y, cp.z, camCenter.x, camCenter.y, camCenter.z, 0.0, 1.0, 0.0);
     glMatrixMode(GL_PROJECTION);
     glLoadIdentity();
     gluPerspective(90, wWidth / wHeight  , 1.0, 100.0);
     // Lights
     glEnable(GL_LIGHTING);
     glEnable(GL_LIGHT0);
+    // Directional light - aka light
     GLfloat light1[] = { 0.0, 1.0, 0.0, 0.0 };
     glLightfv(GL_LIGHT0, GL_POSITION, light1);
     // World
@@ -100,6 +121,7 @@ void display(void) {
 }
 
 void mouseEvent(int button, int state, int x, int y) {
+    lastMouseX = x; lastMouseY = y;
     if(state == 0) lastMouseButton = button;
     if(state == 0 && button == GLUT_LEFT_BUTTON) {
         for(ui_button* b = buttons; b < buttons + sizeof buttons / sizeof(ui_button); b += 1) {
@@ -134,18 +156,44 @@ void mouseMotionEvent(int x, int y) {
             }
         }
     }
+    // TODO: replace with wasd/space/ctrl movement instead
+    else if(lastMouseButton == GLUT_MIDDLE_BUTTON) {
+        // get xz plane rotation
+        float mx = cosf(camRot.y);
+        float mz = -sinf(camRot.y);
+        float m = (x - lastMouseX);
+        
+        camCenter.y += (y - lastMouseY) * 0.5;
+        camCenter.x -= m * mx;
+        camCenter.z -= m * mz;
+        printf("new cam center %f %f %f\n", camCenter.x, camCenter.y, camCenter.z);
+    }
+    else if(lastMouseButton == GLUT_RIGHT_BUTTON) {
+        // rotate the camera
+        camRot.y -= (x - lastMouseX) * PI * 0.01;
+        if(camRot.y > 2 * PI) camRot.y -= 2 * PI;
+        else if(camRot.y < 0.0) camRot.y += 2 * PI;
+        
+        camRot.x = fmin(PI * 0.5, fmax(-PI * 0.5, camRot.x + (y - lastMouseY) * 0.01 * PI));
+    }
+    lastMouseX = x; lastMouseY = y;
     glutPostRedisplay();
 }
 
 void mouseWheelEvent(int wheel, int dir, int x, int y) {
+    char slided = 0;
     for(ui_slider* s = sliders; s < sliders + sizeof sliders / sizeof(ui_slider); s += 1) {
         if(ui_slider_mouse_over(s, x, y)) {
             s->value += dir * 0.05;
             if(s->value < 0.0) s->value = 0.0;
             if(s->value > 1.0) s->value = 1.0;
             printf("Updated %p value to %f\n", s, s->value);
+            slided = 1;
         }
     }
+    if(!slided) {
+        camRadius *= 1.0 + (dir * 0.1);
+    }
     glutPostRedisplay();
 }
 
@@ -173,11 +221,6 @@ int main(int argc, char** argv) {
     glutMouseWheelFunc(mouseWheelEvent);
     glutMotionFunc(mouseMotionEvent);
     
-    /* set projection and camera */
-    glMatrixMode(GL_PROJECTION);
-    glLoadIdentity();
-    gluOrtho2D(0.0, 800.0, 0.0, 500.0);
-    
     glutMainLoop();
     
     return 0;