Initial attempts for a camera state object for easier camera movement.

CMakeLists.txt

@@ -87,6 +87,7 @@ target_sources(vissim PRIVATE
 	src/vissim.cc
 	src/sthstry.c
 	src/simulator.cc
+	src/render_utils.c
 	)
 
 # Tests

src/render_utils.c

@@ -0,0 +1,77 @@
+#include "render_utils.h"
+#include "utils.h"
+
+inline void CameraState_Init(CameraState* camera_state) {
+  // clang-format off
+  static float mtx_identity[16] = {
+      1.f, 0.f, 0.f, 0.f,
+      0.f, 1.f, 0.f, 0.f,
+      0.f, 0.f, 1.f, 0.f,
+      0.f, 0.f, 0.f, 1.f
+  };
+  // clang-format on
+
+  memcpy(&camera_state->mtxView, &mtx_identity, sizeof(camera_state->mtxView));
+}
+
+void CameraState_CalcFromMatrix(CameraState* camera_state, simd4x4f* mtx) {
+  camera_state->pos[0] = mtx->w[0];
+  camera_state->pos[1] = mtx->w[1];
+  camera_state->pos[2] = mtx->w[2];
+
+  float right[3] = {mtx->x[0], mtx->y[0], mtx->z[0]};
+  float up[3] = {mtx->x[1], mtx->y[1], mtx->z[1]};
+  float forward[3] = {-mtx->x[2], -mtx->y[2], -mtx->z[2]};
+
+  camera_state->heading = atan2(forward[2], -forward[0]);
+  camera_state->pitch = asin(-forward[1]);
+
+  gLog("eye: %f %f %f", camera_state->pos[0], camera_state->pos[1], camera_state->pos[2]);
+}
+
+void CameraState_CalcToMatrix(CameraState* camera_state, simd4x4f* mtx) {
+  float sp = sin(camera_state->pitch);
+  float cp = cos(camera_state->pitch);
+  float ch = cos(camera_state->heading);
+  float sh = sin(camera_state->heading);
+
+  const float d = 10.0f;
+
+  simd4f eye = simd4f_create (camera_state->pos[0], camera_state->pos[1], camera_state->pos[2], 1.f);
+  simd4f forward = simd4f_create (-cp * ch * d, -sp * d, cp * sh * d, 1.f);
+  simd4f right = simd4f_cross3 (forward, simd4f_create (0.f, 1.f, 0.f, 1.f));
+  simd4f up = simd4f_cross3(right, forward);
+  simd4f center = simd4f_add(eye, forward);
+
+  simd4x4f_lookat(mtx, eye, center, up);
+}
+
+inline void CameraState_Update(
+    CameraState* camera_state,
+    float dt,
+    float mouse_dx,
+    float mouse_dy,
+    float accel[3]) {
+  CameraState_CalcFromMatrix(camera_state, &camera_state->mtxView);
+
+  camera_state->heading += dt * mouse_dx * M_PI / 180.f;
+  if (camera_state->heading < -M_PI) {
+    camera_state->heading += M_PI;
+  } else if (camera_state->heading > M_PI) {
+    camera_state->heading -= M_PI;
+  }
+  camera_state->heading = dt * mouse_dy * M_PI / 180.f;
+  if (camera_state->heading < -M_PI * 0.49) {
+    camera_state->heading = -M_PI * 0.49;
+  } else if (camera_state->heading > M_PI * 0.49) {
+    camera_state->heading = M_PI * 0.49;
+  }
+
+  for (int i = 0; i < 3; i++) {
+    camera_state->vel[i] += dt * accel[i];
+    camera_state->pos[i] += dt * camera_state->vel[i];
+    camera_state->vel[i] = camera_state->vel[i] * 0.5;
+  }
+
+  CameraState_CalcToMatrix(camera_state, &camera_state->mtxView);
+}

src/render_utils.h

@@ -0,0 +1,36 @@
+//
+// Created by martin on 19.10.21.
+//
+
+#ifndef RBDLSIM_RENDER_UTILS_H
+#define RBDLSIM_RENDER_UTILS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "vectorial/simd4x4f.h"
+
+typedef struct {
+  simd4x4f mtxView;
+  float heading;
+  float pitch;
+  float vel[3];
+  float pos[3];
+} CameraState;
+
+void CameraState_Init(CameraState* camera_state);
+void CameraState_CalcFromMatrix(CameraState* camera_state, simd4x4f* mtx);
+void CameraState_CalcToMatrix(CameraState* camera_state, simd4x4f* mtx);
+void CameraState_Update(
+    CameraState* camera_state,
+    float dt,
+    float mouse_dx,
+    float mouse_dy,
+    float accel[3]);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  //RBDLSIM_RENDER_UTILS_H

src/utils.cc

@@ -9,6 +9,7 @@ Timer* gTimer = &sTimer;
 double gTimeAtStart = 0;
 
 FILE* gLogFile = NULL;
+const int cLogBufferSize = 1024;
 
 void gTimerInit() {
   sTimer.mCurrentTime = 0.;

src/utils.h

@@ -65,7 +65,7 @@ extern FILE* gLogFile;
 
 void LoggingInit();
 
-const int cLogBufferSize = 1024;
+extern const int cLogBufferSize;
 
 inline void gLog(const char* format, ...) {
   assert(gLogFile != NULL);

src/vissim.cc

@@ -23,20 +23,17 @@
 #include "simulator.h"
 #include "srender.h"
 #include "utils.h"
+#include "render_utils.h"
 
 GLFWwindow* gWindow = nullptr;
 GuiInputState* gGuiInputState = nullptr;
+CameraState* gCameraState = nullptr;
 
 // Rendering
 srndr* gRndr = nullptr;
 srview* gView = nullptr;
 srcmdbuf* gRndrCmds = nullptr;
 
-simd4x4f gViewMatrix = {
-    simd4f_create(1.f, 0.f, 0.0, 0.f),
-    simd4f_create(0.f, 1.f, 0.f, 0.f),
-    simd4f_create(0.f, 0.f, 1.f, 0.f),
-    simd4f_create(0.f, 0.f, 0.f, 1.f)};
 simd4x4f gProjMatrix{
     simd4f_create(1.f, 0.f, 0.0, 0.f),
     simd4f_create(0.f, 1.f, 0.f, 0.f),
@@ -221,7 +218,7 @@ void ShowViewManip() {
   ImGui::SetCursorPos(view_manip_widget_pos - ImGui::GetWindowPos());
   ImGui::InvisibleButton("ViewManipulator", view_manip_widget_size);
   ImGuizmo::ViewManipulate(
-      (float*)&(gViewMatrix.x),
+      (float*)&(gCameraState->mtxView.x),
       10.0f,
       view_manip_widget_pos,
       view_manip_widget_size,
@@ -347,7 +344,7 @@ void ShowTransformManip(
   simd4x4f identity_mat;
   simd4x4f_identity(&identity_mat);
 
-  ImGuizmo::Manipulate(
+  bool modified = ImGuizmo::Manipulate(
       cameraView,
       cameraProjection,
       mCurrentGizmoOperation,
@@ -372,7 +369,7 @@ void DoRender() {
   // Render Output
   ImGui::Begin("Render Output", nullptr, ImGuiWindowFlags_NoScrollbar);
 
-  // Update the gViewMatrix
+  // Update the gCameraState->mtxView
   const ImVec2 content_avail = ImGui::GetContentRegionAvail();
   srview_set_size(gView, content_avail.x, content_avail.y);
 
@@ -393,7 +390,7 @@ void DoRender() {
       view_width / view_height,
       0.1f,
       50.f);
-  srview_set_view(gView, gViewMatrix);
+  srview_set_view(gView, gCameraState->mtxView);
   srview_set_proj(gView, gProjMatrix);
 
   // Populate render commands
@@ -426,19 +423,10 @@ void DoRender() {
   ImGuiIO& io = ImGui::GetIO();
 
   ShowViewManip();
-  ShowTransformManip((float*)&(gViewMatrix),
+  ShowTransformManip((float*)&(gCameraState->mtxView),
                      (float*)&(gProjMatrix),
                      (float*)(&gTransformMatrix));
 
-  /*
-  EditTransform(
-      (float*)&(gViewMatrix),
-      (float*)&(gProjMatrix),
-      (float*)(&gTransformMatrix),
-      true,
-      window_pos,
-      window_size);
-*/
   ImGui::End();
 }
 
@@ -521,16 +509,20 @@ int main(void) {
   bool show_demo_window = true;
   ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
 
+  CameraState camera_state;
+  CameraState_Init(&camera_state);
+  gCameraState = &camera_state;
+
   gRndr = srndr_create();
   gView = srview_create();
   gRndrCmds = srcmdbuf_create(1024);
   simulator_init();
 
-  simd4x4f_translation(&gViewMatrix, 0.1f, 0.1f, -0.5f);
+  simd4x4f_translation(&gCameraState->mtxView, 0.1f, 0.1f, -0.5f);
   simd4f eye = simd4f_create(0.f, 3.f, 10.f, 1.f);
 
   simd4x4f_lookat(
-      &gViewMatrix,
+      &gCameraState->mtxView,
       eye,
       simd4f_create(0.f, 0.f, 0.f, 1.f),
       simd4f_create(0.f, 1.f, 0.f, 1.f));
@@ -538,6 +530,8 @@ int main(void) {
   simd4x4f scale_mat = simd4x4f_scale(simd4f_create(1.f, 1.f, 1.f, 1.f));
   simd4x4f_mul(&gTransformMatrix, &scale_mat, &gTransformMatrix);
 
+  CameraState_CalcFromMatrix(gCameraState, &gCameraState->mtxView);
+
   while (!glfwWindowShouldClose(gWindow)) {
     FrameMark;
     frame_counter++;
@@ -582,9 +576,24 @@ int main(void) {
         ImGui::EndMenu();
       }
 
+
       float menu_bar_height = ImGui::GetWindowHeight();
       ImGui::EndMainMenuBar();
 
+      CameraState_CalcFromMatrix(gCameraState, &gCameraState->mtxView);
+
+      ImGui::Begin("HeadingPitch");
+
+      bool changed = false;
+      changed = ImGui::SliderFloat("Heading", &gCameraState->heading, -M_PI * 0.98, M_PI * 0.98);
+      changed = changed || ImGui::SliderFloat("Pitch", &gCameraState->pitch, -M_PI * 0.98, M_PI * 0.98);
+
+      if (changed) {
+        //CameraState_CalcToMatrix(gCameraState, &gCameraState->mtxView);
+      }
+
+      ImGui::End();
+
       if (show_demo_window) ImGui::ShowDemoWindow();
 
       ShowDockspace(true);