quick WIP for GLSL transpose for the shakycam effect

sz3 · Feb 20, 2021 · 0de861b · 0de861b
1 parent 9b90e78
commit 0de861b
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Showing 2 changed files with 33 additions and 5 deletions.
diff --git a/src/lib/gui/gl_2d_display.h b/src/lib/gui/gl_2d_display.h
@@ -60,8 +60,13 @@ class gl_2d_display
 
  // pass in rotation matrix
  GLuint rotateUniform = glGetUniformLocation(prog, "rot");
- std::array<GLfloat, 4> vals = rotation_matrix();
- glUniformMatrix2fv(rotateUniform, 1, false, vals.data());
+ std::array<GLfloat, 4> rot = rotation_matrix();
+ glUniformMatrix2fv(rotateUniform, 1, false, rot.data());
+
+ // pass in transform vector
+ GLuint transformUniform = glGetUniformLocation(prog, "tform");
+ std::pair<float, float> tform = shake_transform();
+ glUniform2f(transformUniform, tform.first, tform.second);
 
  // Draw
  glDrawArrays(GL_TRIANGLES, 0, 6);
@@ -87,6 +92,12 @@ class gl_2d_display
  _rotation = 0;
  }
 
+ void shake(unsigned i=1)
+ {
+ if (i == 0 or ++_shake >= 8)
+ _shake = 0;
+ }
+
  std::array<GLfloat, 4> rotation_matrix() const
  {
  // just using sin and cos is probably better?
@@ -95,15 +106,23 @@ class gl_2d_display
  default:
  case 0:
  return {-1, 0, 0, 1};
- case 1: // right 90
- return {0, 1, 1, 0};
- case 2: // right 180
+ case 1: // right 180
  return {1, 0, 0, -1};
+ case 2: // right 90
+ return {0, 1, 1, 0};
  case 3: // right 270
  return {0, -1, -1, 0};
  }
  }
 
+ std::pair<float, float> shake_transform() const
+ {
+ static constexpr std::array<std::pair<float, float>, 8> SHAKE_POS = {{
+ {0, 0}, {-.008, -.008}, {0, 0}, {.008, .008}, {0, 0}, {-.008, .008}, {0, 0}, {.008, -.008}
+ }};
+ return SHAKE_POS[_shake];
+ }
+
 protected:
  static std::shared_ptr<cimbar::gl_program> create()
  {
@@ -116,13 +135,15 @@ class gl_2d_display
  */
  static const std::string VERTEX_SHADER_SRC = R"(#version 300 es
  uniform mat2 rot;
+ uniform vec2 tform;
  in vec4 vert;
  out vec2 texCoord;
  void main() {
  gl_Position = vec4(vert.x, vert.y, 0.0f, 1.0f);
  vec2 ori = vec2(vert.x, vert.y);
  ori *= rot;
  texCoord = vec2(1.0f - ori.x, 1.0f - ori.y) / 2.0;
+ texCoord += tform;
  })";
 
  static const std::string FRAGMENT_SHADER_SRC = R"(#version 300 es
@@ -145,6 +166,7 @@ class gl_2d_display
  GLuint _vao;
  unsigned _i = 0;
  unsigned _rotation = 0;
+ unsigned _shake = 0;
 };
 
 }
diff --git a/src/lib/gui/window_glfw.h b/src/lib/gui/window_glfw.h
@@ -61,6 +61,12 @@ class window_glfw : public window_interface<window_glfw>
  _display->rotate(i);
  }
 
+ void shake(unsigned i=1)
+ {
+ if (_display)
+ _display->shake(i);
+ }
+
  void clear()
  {
  if (_display)