cube to equirect conversion using shader, save latlong to file

data/layout.xml

@@ -370,7 +370,7 @@
             <icon width="100%" height="100%" icon="disk"/>
           </button-custom>-->
 
-          <button id="btn-switch" width="50" height="50" margin="0 0 5 0" text="Switch"/>
+          <button id="btn-switch" width="50" height="50" margin="0 0 5 0" text="Save"/>
           <button id="btn-undo" width="50" height="50" margin="0 0 5 0" text="Undo"/>
           <button id="btn-close" width="50" height="50" margin="0 0 5 0" text="Clear"/>
           <button-custom id="btn-bucket" width="50" height="50" margin="0 0 5 0" thickness="1" border-color=".1" pad="2">

engine/app.cpp

@@ -262,6 +262,35 @@ void App::initShaders()
         "   frag = mix(c1, c2, alpha);\n"
         "}";
 
+    static const char* shader_equirect_v =
+        SHADER_VERSION
+        "#define PI 3.1415926535897932384626433832795\n"
+        "#define TWO_PI 6.283185307179586476925286766559\n"
+        "uniform mat4 mvp;\n"
+        "in vec4 pos;\n"
+        "in vec2 uvs;\n"
+        "out vec2 uv;\n"
+        "void main(){\n"
+        "   uv = (vec2(1.0) - uvs + vec2(0.25,0.0)) * vec2(TWO_PI, PI);\n"
+        "   gl_Position = mvp * vec4(pos.xyz, 1.0);\n"
+        "}";
+    static const char* shader_equirect_f =
+        SHADER_VERSION
+        "uniform samplerCube tex;\n"
+        "in mediump vec2 uv;\n"
+        "out mediump vec4 frag;\n"
+        "void main(){\n"
+        "   float anglex = uv.x;\n"
+        "   float angley = uv.y;\n"
+        "   float sx = sin(anglex);\n"
+        "   float cx = cos(anglex);\n"
+        "   vec3 dir = vec3(0.0, 0.0, 0.0);\n"
+        "   dir.x = sin(angley) * cx;\n"
+        "   dir.y = cos(angley);\n"
+        "   dir.z = sin(angley) * sx;\n"
+        "   frag = texture(tex, dir);\n"
+        "}";
+
     LOG("initializing shaders");
     if (!ShaderManager::create(kShader::Texture, shader_v, shader_f))
         LOG("Failed to create shader Texture");
@@ -287,6 +316,8 @@ void App::initShaders()
         LOG("Failed to create shader StrokeLayer");
     if (!ShaderManager::create(kShader::Checkerboard, shader_checkerboard_v, shader_checkerboard_f))
         LOG("Failed to create shader Checkerboard");
+    if (!ShaderManager::create(kShader::Equirect, shader_equirect_v, shader_equirect_f))
+        LOG("Failed to create shader Equirect");
     LOG("shaders initialized");
 }
 
@@ -444,7 +475,7 @@ void App::initLayout()
                     //button->m_text->set_text(canvas->m_canvas->m_use_instanced ? "INST" : "NORM");
                 }
             };
-            button->m_text->set_text("NORM");
+            //button->m_text->set_text("NORM");
         }
         if (auto* button = layout[main_id]->find<NodeButton>("btn-undo"))
         {

engine/app.h

@@ -11,7 +11,7 @@ class App
 {
 public:
     static App I;
-    std::string data_path;
+    std::string data_path{ "." };
     Sampler sampler;
     Texture2D tex;
     LayoutManager layout;

engine/canvas.cpp

@@ -346,6 +346,7 @@ void ui::Canvas::resize(int width, int height)
     {
         l.create(width, height, "");
     }
+    m_latlong.create(width * 4, height * 2); // NOTE: w and h must be equal to make sense
 }
 bool ui::Canvas::create(int width, int height)
 {
@@ -366,6 +367,7 @@ bool ui::Canvas::create(int width, int height)
     {
         l.create(width, height, "");
     }
+    m_latlong.create(width * 4, height * 2); // NOTE: w and h must be equal to make sense
     return true;
 }
 
@@ -398,6 +400,7 @@ void ui::Canvas::clear_context()
         m_tex[i].destroy();
         m_tex2[i].destroy();
     }
+    m_latlong.destroy();
 };
 
 void ui::Canvas::save(std::string data_path)
@@ -413,6 +416,18 @@ void ui::Canvas::save(std::string data_path)
     glViewport(0, 0, m_width, m_height);
     glDisable(GL_BLEND);
 
+    glGenTextures(1, &cube_id);
+    glBindTexture(GL_TEXTURE_CUBE_MAP, cube_id);
+    for (GLuint i = 0; i < 6; i++)
+        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA8, m_width, m_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+    int faces[]{
+        GL_TEXTURE_CUBE_MAP_NEGATIVE_Z, // front
+        GL_TEXTURE_CUBE_MAP_NEGATIVE_X, // right
+        GL_TEXTURE_CUBE_MAP_POSITIVE_Z, // back
+        GL_TEXTURE_CUBE_MAP_POSITIVE_X, // left
+        GL_TEXTURE_CUBE_MAP_NEGATIVE_Y, // top
+        GL_TEXTURE_CUBE_MAP_POSITIVE_Y, // bottom
+    };
     for (int i = 0; i < 6; i++)
     {
         m_tmp[i].bindFramebuffer();
@@ -421,7 +436,7 @@ void ui::Canvas::save(std::string data_path)
         for (auto layer_index : m_order)
         {
             // copy to tmp2 for layer blending
-            glActiveTexture(GL_TEXTURE0);
+            glActiveTexture(GL_TEXTURE0); // TODO: maybe remove this line
             m_tex2[i].bind();
             glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, m_width, m_height);
             m_tex2[i].unbind();
@@ -443,17 +458,42 @@ void ui::Canvas::save(std::string data_path)
             m_layers[layer_index].m_rtt[i].unbindTexture();
         }
 
+        // copy result to cubemap
+        glBindTexture(GL_TEXTURE_CUBE_MAP, cube_id);
+        glCopyTexImage2D(faces[i], 0, GL_RGBA8, 0, 0, m_width, m_height, 0);
+        glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
+
         m_tmp[i].unbindFramebuffer();
     }
 
-    auto data = std::make_unique<uint8_t[]>(m_tmp[0].bytes());
+//     auto data = std::make_unique<uint8_t[]>(m_tmp[0].bytes());
-    for (int i = 0; i < 6; i++)
+//     for (int i = 0; i < 6; i++)
+//     {
+//         m_tmp[i].readTextureData(data.get());
+//         static char name[128];
+//         sprintf(name, "%s/Face%d.png", data_path.c_str(), i);
+//         LOG("writing %s", name);
+//         //int ret = stbi_write_png(name, m_tmp[i].getWidth(), m_tmp[i].getHeight(), 4, data.get(), m_tmp[i].stride());
+//     }
+
+    glViewport(0, 0, m_latlong.getWidth(), m_latlong.getHeight());
+    m_latlong.bindFramebuffer();
+    ui::ShaderManager::use(kShader::Equirect);
+    ui::ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-.5f, .5f, -.5f, .5f, -1.f, 1.f));
+    ui::ShaderManager::u_int(kShaderUniform::Tex, 0);
+    glBindTexture(GL_TEXTURE_CUBE_MAP, cube_id);
+    m_sampler.bind(0);
+    m_plane.draw_fill();
+    m_sampler.unbind();
+    glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
+    m_latlong.unbindFramebuffer();
     {
-        m_tmp[i].readTextureData(data.get());
+        auto latlong_data = std::make_unique<uint8_t[]>(m_latlong.bytes());
+        m_latlong.readTextureData(latlong_data.get());
         static char name[128];
-        sprintf(name, "%s/Face%d.png", data_path.c_str(), i);
+        sprintf(name, "%s/latlong.png", data_path.c_str());
         LOG("writing %s", name);
-        int ret = stbi_write_png(name, m_tmp[i].getWidth(), m_tmp[i].getHeight(), 4, data.get(), m_tmp[i].stride());
+        int ret = stbi_write_png(name, m_latlong.getWidth(), m_latlong.getHeight(), 4, latlong_data.get(), m_latlong.stride());
     }
 
     // restore viewport and clear color states

engine/canvas.h

@@ -60,6 +60,9 @@ public:
     glm::vec2 m_cam_rot;
     float m_cam_fov = 85;
 
+    GLuint cube_id;
+    RTT m_latlong;
+
     std::vector<Layer::Snapshot> m_layers_snapshot;
 
     bool create(int width, int height);

engine/layout.h

@@ -1969,6 +1969,13 @@ public:
             }
         }
 
+        //ui::ShaderManager::use(kShader::Equirect);
+        //ui::ShaderManager::u_mat4(kShaderUniform::MVP, glm::scale(glm::vec3(.5, .5, 1)));
+        //ui::ShaderManager::u_int(kShaderUniform::Tex, 0);
+        //glBindTexture(GL_TEXTURE_CUBE_MAP, m_canvas->cube_id);
+        //m_face_plane.draw_fill();
+        //glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
+        
         blend ? glEnable(GL_BLEND) : glDisable(GL_BLEND);
         m_sampler.unbind();
         glViewport(vp[0], vp[1], vp[2], vp[3]);

engine/rtt.h

@@ -16,6 +16,7 @@ public:
 
     void destroy();
     bool create(int width, int height, int tex = -1);
+    bool recreate() { return create(w, h); }
     void clear(glm::vec4 color = glm::vec4(0));
     void readTextureData(uint8_t* buffer);
     uint8_t* createBuffer();

engine/shader.h

@@ -30,6 +30,7 @@ enum class kShader : uint16_t
     StrokeErase = const_hash("stroke-erase"),
     StrokeLayer = const_hash("stroke-layer"),
     Checkerboard= const_hash("checkerboard"),
+    Equirect    = const_hash("equirect"),
 };
 
 class Shader

engine/texture.cpp

@@ -97,6 +97,7 @@ void Sampler::set(GLint filter /*= GL_LINEAR*/, GLint wrap /*= GL_CLAMP_TO_EDGE*
 #if USE_SAMPLER
     glSamplerParameteri(id, GL_TEXTURE_WRAP_S, wrap);
     glSamplerParameteri(id, GL_TEXTURE_WRAP_T, wrap);
+    glSamplerParameteri(id, GL_TEXTURE_WRAP_R, wrap);
     glSamplerParameteri(id, GL_TEXTURE_MIN_FILTER, filter);
     glSamplerParameteri(id, GL_TEXTURE_MAG_FILTER, filter);
 #endif // USE_SAMPLER