From ba028ae4dbbf93a461c9c9474889d04e640f64e0 Mon Sep 17 00:00:00 2001
From: Samuel Fadel <samuel@nihil.ws>
Date: Sun, 4 Jun 2023 18:47:27 +0200
Subject: More fixes to rendering, same as original except for point outlines.

---
 scatterplot.cpp | 47 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 43 insertions(+), 4 deletions(-)

(limited to 'scatterplot.cpp')

diff --git a/scatterplot.cpp b/scatterplot.cpp
index a7194e8..64859b3 100644
--- a/scatterplot.cpp
+++ b/scatterplot.cpp
@@ -6,6 +6,9 @@
 #include "colormap.h"
 #include "continuouscolorscale.h"
 
+// Samples used in multisampling for rendering
+static const size_t NUM_SAMPLES = 8;
+
 // Glyphs settings
 static const Color DEFAULT_GLYPH_COLOR(255, 255, 255);
 static const float DEFAULT_GLYPH_SIZE = 8.0f;
@@ -66,6 +69,7 @@ out vec4 FragColor;
 
 void main()
 {
+    gl_FragDepth = gl_PrimitiveID / 3000;
     FragColor = color;
     // FragColor = vec4(1.0);
 }
@@ -113,6 +117,7 @@ out vec4 FragColor;
 
 void main()
 {
+    gl_FragDepth = gl_PrimitiveID / 2000;
     FragColor = vec4(0.0, 0.0, 0.0, 1.0);
 }
 )EOF";
@@ -166,6 +171,7 @@ Scatterplot::Scatterplot()
     , m_shouldUpdateMaterials(false)
 {
     glGenFramebuffers(1, &m_FBO);
+    glGenFramebuffers(1, &m_outFBO);
 
     glGenBuffers(1, &m_pointsVBO);
     glGenBuffers(1, &m_valuesVBO);
@@ -179,9 +185,11 @@ Scatterplot::Scatterplot()
     glBindBuffer(GL_ARRAY_BUFFER, m_valuesVBO);
     glEnableVertexAttribArray(1);
     glVertexAttribPointer(1, 1, GL_FLOAT, GL_FALSE, 0, nullptr);
-    glVertexAttribDivisor(1, 1);
+    // glVertexAttribDivisor(1, 1);
     glBindVertexArray(0);
 
+    glGenTextures(1, &m_depthTex);
+    glGenTextures(1, &m_tex);
     glGenTextures(1, &m_outTex);
 
     m_shader = std::make_unique<Shader>(
@@ -208,6 +216,22 @@ void Scatterplot::setSize(size_t width, size_t height)
     m_width = width;
     m_height = height;
 
+    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_tex);
+    glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, NUM_SAMPLES,
+                            GL_RGBA, m_width, m_height, GL_TRUE);
+    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0);
+
+    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_depthTex);
+    glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameteri(GL_TEXTURE_2D_MULTISAMPLE, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, NUM_SAMPLES,
+                            GL_DEPTH_COMPONENT, m_width, m_height, GL_TRUE);
+    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, 0);
+
     glBindTexture(GL_TEXTURE_2D, m_outTex);
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, m_width, m_height, 0, GL_RGBA,
                  GL_FLOAT, 0);
@@ -386,7 +410,9 @@ void Scatterplot::draw()
 
     glBindFramebuffer(GL_FRAMEBUFFER, m_FBO);
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
-                           GL_TEXTURE_2D, m_outTex, 0);
+                           GL_TEXTURE_2D_MULTISAMPLE, m_tex, 0);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
+                           GL_TEXTURE_2D_MULTISAMPLE, m_depthTex, 0);
 
     glViewport(0, 0, m_width, m_height);
     m_shader->use();
@@ -398,24 +424,37 @@ void Scatterplot::draw()
     glBindTexture(GL_TEXTURE_2D, m_colormapTex);
     m_shader->setUniform("colormap", 0);
 
+    glEnable(GL_DEPTH_TEST);
     glEnable(GL_BLEND);
     // glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
     glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
-    glClear(GL_COLOR_BUFFER_BIT);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     glBindVertexArray(m_VAO);
     glDrawArrays(GL_POINTS, 0, m_points.size());
     m_shader->release();
 
     // Swap out shaders to draw outline
+    glLineWidth(GLYPH_OUTLINE_WIDTH);
     m_shaderOutline->use();
     m_shaderOutline->setUniform("transform", m_transform);
     m_shaderOutline->setUniform("size", m_glyphSize / m_width);
     m_shaderOutline->setUniform("colormap", 0);
     glDrawArrays(GL_POINTS, 0, m_points.size());
-
     glBindVertexArray(0);
     m_shaderOutline->release();
+    glLineWidth(1.0f);
+    glDisable(GL_DEPTH_TEST);
+
+    glBindFramebuffer(GL_FRAMEBUFFER, m_outFBO);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
+                           GL_TEXTURE_2D, m_outTex, 0);
+
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, m_FBO);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_outFBO);
+    glBlitFramebuffer(0, 0, m_width, m_height,
+                      0, 0, m_width, m_height,
+                      GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT, GL_NEAREST);
 
     /*
     GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
-- 
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