From 071cc0ec1150be27e154750fc18ba11826b2289f Mon Sep 17 00:00:00 2001
From: Syed Ahmed Hussain <ahmedhus22@gmail.com>
Date: Sun, 2 Jun 2024 22:24:38 +0530
Subject: [PATCH] add colormap texture for multistate colors

---
 pyaccell/pyaccell/automata.cpp | 36 +++++++++++++++++++++++++++++++++-
 pyaccell/pyaccell/automata.hpp |  1 +
 pyaccell/pyaccell/sim.fs       |  3 ++-
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/pyaccell/pyaccell/automata.cpp b/pyaccell/pyaccell/automata.cpp
index e46f52d..77ad8ce 100644
--- a/pyaccell/pyaccell/automata.cpp
+++ b/pyaccell/pyaccell/automata.cpp
@@ -122,11 +122,13 @@ int pyaccell::Automata::run(int iterations)
     unsigned int textureBinomials = pyaccell::generate_binomials();
     unsigned int indices = pyaccell::no_of_indices(states);
     unsigned int textureRule = pyaccell::generate_rule(&rule[0], indices, states);
-    enum SAMPLER {BINOMIAL = 1, INPUT = 2, RULE = 3};
+    unsigned int textureColorMap = create_color_map();
+    enum SAMPLER {BINOMIAL = 1, INPUT = 2, RULE = 3, COLOR_MAP=4};
     simShader.use();
     simShader.setInt("uBinomial", BINOMIAL);
     simShader.setInt("inputStates", INPUT);
     simShader.setInt("rule", RULE);
+    simShader.setInt("colorMap", COLOR_MAP);
     simShader.setInt("numStates", states);
     simShader.setInt("inputWidth", sim_width);
     simShader.setInt("inputHeight", sim_height);
@@ -164,6 +166,8 @@ int pyaccell::Automata::run(int iterations)
         glBindTexture(GL_TEXTURE_2D, textureBinomials);
         glActiveTexture(GL_TEXTURE0 + RULE);
         glBindTexture(GL_TEXTURE_2D, textureRule);
+        glActiveTexture(GL_TEXTURE0 + COLOR_MAP);
+        glBindTexture(GL_TEXTURE_2D, textureColorMap);
         glActiveTexture(GL_TEXTURE0 + INPUT);
         glBindTexture(GL_TEXTURE_2D, textureInput[input_index]);
         glDrawArrays(GL_TRIANGLES, 0, 6);
@@ -207,6 +211,36 @@ std::vector<unsigned int> pyaccell::Automata::get_texture_data(unsigned int text
     return data;
 }
 
+unsigned int pyaccell::Automata::create_color_map()
+{
+    unsigned int texture;
+    glGenTextures(1, &texture);
+    glBindTexture(GL_TEXTURE_2D, texture);
+    unsigned char *data = new unsigned char[MAX_STATES * 3];
+    for (int i=0; i<3; ++i) data[i] = 20; // state 0 (dark)
+    for (int i=3; i<6; ++i) data[i] = 255; // state 1 (white)
+    data[6] = 255; data[7] = 20; data[8] = 20; // state 3 (red)
+    // remaining states (random colors)
+    unsigned char color[] = {(char)10, (char)20, (char)40};
+    for (int i=9; i<MAX_STATES*3; i+=3) {
+        color[0] *= 2;
+        color[1] *= 1.5;
+        color[2] += 20;
+
+        data[i] = color[0];
+        data[i + 1] = color[1];
+        data[i + 2] = color[2];
+    }
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, MAX_STATES, 1, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+    delete[] data;
+    return texture;
+}
+
 // process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
 void pyaccell::Automata::processInput(GLFWwindow *window)
 {
diff --git a/pyaccell/pyaccell/automata.hpp b/pyaccell/pyaccell/automata.hpp
index a93689a..ef5bfe4 100644
--- a/pyaccell/pyaccell/automata.hpp
+++ b/pyaccell/pyaccell/automata.hpp
@@ -18,6 +18,7 @@ namespace pyaccell {
         private:
             void processInput(GLFWwindow *window);
             std::vector<unsigned int> get_texture_data(unsigned int texture, const unsigned int width, const unsigned int height);
+            unsigned int create_color_map();
             enum RUN_TYPE {NO_FINAL_STATE, FINAL_STATE};
     };
 }
\ No newline at end of file
diff --git a/pyaccell/pyaccell/sim.fs b/pyaccell/pyaccell/sim.fs
index bc41786..3593e50 100644
--- a/pyaccell/pyaccell/sim.fs
+++ b/pyaccell/pyaccell/sim.fs
@@ -7,6 +7,7 @@ in vec2 TexCoords;
 uniform usampler2D uBinomial;
 uniform usampler2D inputStates;
 uniform usampler2D rule;
+uniform sampler2D colorMap;
 uniform int numStates;
 uniform int inputWidth; // width used to create input texture
 uniform int inputHeight;
@@ -45,5 +46,5 @@ void main()
     uint newstate = texelFetch(rule, ivec2(index, curstate), 0).r;
     
     nextstate = newstate;
-    col = vec3(float(nextstate));
+    col = texture(colorMap, vec2((float(nextstate) + 0.5) / 14.0, 0.5)).rgb;
 }
\ No newline at end of file