archivemuh

archive/dusksdl2/display/camera/camera.c

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+/**
+ * Copyright (c) 2025 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "camera.h"
+#include "display/render.h"
+
+#include "world/overworld.h"
+
+void cameraUIPush(void) {
+  glPushMatrix();
+
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+
+  glViewport(0, 0, RENDER_WIDTH, RENDER_HEIGHT);
+
+  mat4 ortho;
+  glm_ortho(
+    0.0f, (float_t)RENDER_WIDTH,
+    (float_t)RENDER_HEIGHT, 0.0f,
+    -1.0f, 1.0f,
+    ortho
+  );
+  glLoadMatrixf((const GLfloat*)ortho);
+
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+}
+
+void cameraUIPop(void) {
+  glPopMatrix();
+}
+
+void cameraScreenPush(void) {
+  glPushMatrix();
+
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+
+  mat4 ortho;
+  #if RENDER_USE_FRAMEBUFFER
+    int32_t windowWidth, windowHeight;
+    SDL_GetWindowSize(RENDER_WINDOW, &windowWidth, &windowHeight);
+
+    glViewport(0, 0, windowWidth, windowHeight);
+    glm_ortho(
+      0.0f, (float_t) windowWidth,
+      (float_t)windowHeight, 0.0f,
+      -1.0f, 1.0f,
+      ortho
+    );
+  #else
+    glm_ortho(
+      0.0f, (float_t)RENDER_WIDTH,
+      (float_t)RENDER_HEIGHT, 0.0f,
+      -1.0f, 1.0f,
+      ortho
+    );
+  #endif
+  glLoadMatrixf((const GLfloat*)ortho);
+
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+}
+
+void cameraScreenPop(void) {
+  glPopMatrix();
+}
+
+void cameraOverworldPush(void) {
+  glPushMatrix();
+  glLoadIdentity();
+
+  #if RENDER_USE_FRAMEBUFFER
+    glViewport(0, 0, RENDER_WIDTH, RENDER_HEIGHT);
+  #endif
+
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+
+  const float_t fov = glm_rad(75.0f);
+  const float_t camOffset = 12.0f;
+  const float_t aspect = (float_t)RENDER_WIDTH / (float_t)RENDER_HEIGHT;
+  const float_t pixelPerfectOffset = (
+    tanf((glm_rad(180) - fov) / 2.0f) *
+    ((float_t)RENDER_HEIGHT/ 2.0f)
+  );
+
+  vec3 look = {
+    OVERWORLD_CAMERA_X,
+    OVERWORLD_CAMERA_Y,
+    0.0f
+  };
+  vec3 eye = {
+    look[0],
+    look[1] + camOffset,
+    look[2] + pixelPerfectOffset
+  };
+  vec3 up = { 0.0f, 1.0f, 0.0f };
+
+  mat4 proj;
+  glm_perspective(fov, aspect, 0.1f, 1000.0f, proj);
+  
+  // Flips rendering on the Y axis, so that it is still right-down even in 3D;
+  proj[1][1] = -proj[1][1];
+
+  mat4 view;
+  glm_lookat(eye, look, up, view);
+
+  mat4 pv;
+  glm_mat4_mul(proj, view, pv);
+
+  glLoadMatrixf((const GLfloat*)pv);
+
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+}
+
+void cameraOverworldPop(void) {
+  glPopMatrix();
+}