Merge branch 'lensDistortion' into 'master'

ENH: added lens distortion to Vulkan engine

See merge request iMSTK/iMSTK!282

CMake/imstkCopyAndCompileShaders.cmake

@@ -30,6 +30,7 @@ function(CopyAndCompileShaders)
       compileShaders(PostProcessing/postprocess_vert.vert PostProcessing/postprocess_vert.spv)
       compileShaders(PostProcessing/postprocess_frag.frag PostProcessing/postprocess_frag.spv)
       compileShaders(PostProcessing/sss_frag.frag PostProcessing/sss_frag.spv)
+      compileShaders(PostProcessing/lens_distortion_frag.frag PostProcessing/lens_distortion_frag.spv)
       compileShaders(PostProcessing/composite_frag.frag PostProcessing/composite_frag.spv)
       compileShaders(PostProcessing/bloom_threshold_frag.frag PostProcessing/bloom_threshold_frag.spv)
       compileShaders(PostProcessing/blur_horizontal_frag.frag PostProcessing/blur_horizontal_frag.spv)

Source/Rendering/VulkanRenderer/PostProcessing/imstkVulkanPostProcessingChain.cpp

@@ -130,6 +130,19 @@ VulkanPostProcessingChain::VulkanPostProcessingChain(VulkanRenderer * renderer)
         m_postProcesses.push_back(bloomCompositePass);
         this->incrementBufferNumbers();
     }
+
+    // Lens distortion
+    if (renderer->m_enableLensDistortion)
+    {
+        auto lensDistortionPass = std::make_shared<VulkanPostProcess>(renderer);
+        lensDistortionPass->addInputImage(&renderer->m_HDRImageSampler, &renderer->m_HDRImageView[m_lastOutput][0]);
+        lensDistortionPass->addInputImage(&renderer->m_HDRImageSampler, &renderer->m_HDRImageView[m_lastInput][0]);
+        lensDistortionPass->m_framebuffer->setColor(&renderer->m_HDRImageView[m_lastInput][0], VK_FORMAT_R16G16B16A16_SFLOAT);
+        lensDistortionPass->initialize(renderer, "./Shaders/VulkanShaders/PostProcessing/lens_distortion_frag.spv");
+        lensDistortionPass->m_pushConstantData[0] = renderer->m_lensDistortionFactor;
+        m_postProcesses.push_back(lensDistortionPass);
+        this->incrementBufferNumbers();
+    }
 }
 
 std::vector<std::shared_ptr<VulkanPostProcess>>&

Source/Rendering/VulkanRenderer/VulkanShaders/PostProcessing/lens_distortion_frag.frag

+#version 460
+
+layout (set = 0, binding = 0) uniform sampler2D colorTexture;
+
+layout (location = 0) out vec4 finalColor;
+
+layout (location = 3) in vertexData{
+    vec2 uv;
+}vertex;
+
+layout (push_constant) uniform pushConstants
+{
+    float distortion;
+}constants;
+
+// Equation based on:
+// Fitzgibbon, Andrew W. "Simulataneous linear estimation of multiple view
+// geometry and lens distortion." Proceedings of the 2001 IEEE Computer Society
+// Conference on Computer Vision and Pattern Recognition. CVPR 2001. Vol. 1,
+// 2001.
+vec2 distortCoordinate(vec2 coordinate, float distortion)
+{
+    // Center coordinate and normalize between -1 and 1
+    vec2 c = (coordinate * 2.0) - 1.0;
+
+    // Compute undistorted distance
+    float d1 = distance(c, vec2(0));
+
+    // Compute distorted distance
+    float d2 = d1 / (1 - (distortion * d1 * d1));
+
+    // Apply distortion
+    c *= (d2 / d1);
+
+    // Restore original coordinate space
+    c = (c + 1.0) / 2.0;
+
+    return c;
+}
+
+void main(void)
+{
+    vec2 totalLength = distortCoordinate(vec2(0.5, 1.0), constants.distortion);
+    vec2 distortedCoordinate = distortCoordinate(vertex.uv, constants.distortion) - vec2(0.5);
+    distortedCoordinate /= (distance(totalLength, vec2(0.5)) * 2.0);
+    distortedCoordinate += vec2(0.5);
+
+    finalColor = texture(colorTexture, distortedCoordinate);
+}
\ No newline at end of file

Source/Rendering/VulkanRenderer/imstkVulkanRenderer.cpp

@@ -1500,6 +1500,26 @@ VulkanRenderer::setBloomOff()
     m_postProcessingChain->m_bloom = false;
 }
 
+void
+VulkanRenderer::enableLensDistortion(const float distortion)
+{
+    float d = distortion;
+    if (distortion >= 1.0f)
+    {
+        d = 0.99f;
+        LOG(WARNING) << "Distortion invalid (>= 1.0f), clamped to 0.99f";
+    }
+
+    if (distortion <= -1.0f)
+    {
+        d = -0.99f;
+        LOG(WARNING) << "Distortion invalid (<= -1.0f), clamped to -0.99f";
+    }
+
+    m_enableLensDistortion = true;
+    m_lensDistortionFactor = d;
+}
+
 void
 VulkanRenderer::setCommandBufferState(VkCommandBuffer * commandBuffer, uint32_t width, uint32_t height)
 {

Source/Rendering/VulkanRenderer/imstkVulkanRenderer.h

@@ -76,6 +76,8 @@ public:
     void setBloomOn();
     void setBloomOff();
 
+    void enableLensDistortion(const float distortion);
+
 protected:
     friend class VulkanViewer;
     friend class VulkanMaterialDelegate;
@@ -313,6 +315,9 @@ protected:
     uint32_t m_shadowMapResolution = 2048;
     std::vector<glm::mat4> m_lightMatrices;
 
+    bool m_enableLensDistortion = false;
+    float m_lensDistortionFactor = 0.0f;
+
     std::vector<std::shared_ptr<VulkanRenderDelegate>> m_renderDelegates;
 
     uint32_t m_renderQueueFamily = 0;

Source/SimulationManager/VulkanRenderer/imstkVulkanViewer.cpp

@@ -86,6 +86,12 @@ VulkanViewer::setResolution(unsigned int width, unsigned int height)
     m_height = height;
 }
 
+void
+VulkanViewer::enableLensDistortion(const float distortion)
+{
+    m_renderer->enableLensDistortion(distortion);
+}
+
 void
 VulkanViewer::startRenderingLoop()
 {

Source/SimulationManager/VulkanRenderer/imstkVulkanViewer.h

@@ -88,6 +88,14 @@ public:
     ///
     void setResolution(unsigned int width, unsigned int height);
 
+    ///
+    /// \brief Enable lens distortion
+    /// \param distortion Distortion factor to apply: range is (-1.0, 1.0)
+    /// A negative distortion value will cause pincushion distortion. A
+    /// positive value will cause barrel distortion.
+    ///
+    void enableLensDistortion(const float distortion);
+
 protected:
     friend class VulkanInteractorStyle;
     friend class VulkanInteractorStyleFreeCamera;