Canvas implementation and add build of LodePNG

CMakeLists.txt

@@ -17,6 +17,12 @@ ExternalProject_Add(googletest
         TEST_COMMAND      ""
 )
 
+# LodePNG don't make a .a or .so, so let's build a library here
+add_library(LodePNG STATIC)
+set(LODEPNG_INCLUDE_FOLDER ${CMAKE_CURRENT_SOURCE_DIR}/external/lodepng)
+target_sources(LodePNG PRIVATE external/lodepng/lodepng.cpp external/lodepng/lodepng.h)
+
+
 # Main app
 add_subdirectory(source)
 # Unit Tests

source/CMakeLists.txt

@@ -3,14 +3,14 @@
 # First most is build as a library
 add_library(rayonnement STATIC)
 
-set(RAY_HEADERS include/tuples.h include/math_helper.h include/colour.h)
-set(RAY_SOURCES tuples.cpp math_helper.cpp colour.cpp)
+set(RAY_HEADERS include/tuples.h include/math_helper.h include/colour.h include/canvas.h)
+set(RAY_SOURCES tuples.cpp math_helper.cpp colour.cpp canvas.cpp)
 
 target_include_directories(rayonnement PUBLIC include)
 target_sources(rayonnement PRIVATE ${RAY_HEADERS} ${RAY_SOURCES})
-
+target_link_libraries(rayonnement LodePNG)
 
 # Second we build the main executable
 add_executable(dorayme main.cpp)
-target_include_directories(rayonnement PUBLIC include)
+target_include_directories(rayonnement PUBLIC include ${LODEPNG_INCLUDE_FOLDER})
 target_link_libraries(dorayme rayonnement)

source/canvas.cpp

@@ -0,0 +1,57 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Canvas implementation
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+
+#include <canvas.h>
+#include <lodepng.h>
+
+#define BPP (24)
+#define BytePP (BPP / 8)
+
+#define MIN(_a, _b) ((_a)<(_b)?(_a):(_b))
+#define MAX(_a, _b) ((_a)>(_b)?(_a):(_b))
+
+Canvas::Canvas(uint32_t width, uint32_t height) : width(width), height(height)
+{
+    this->bitmap = (uint8_t *)calloc(4, width * height);
+    this->stride = BytePP * width;
+}
+
+Canvas::~Canvas()
+{
+    if (this->bitmap != nullptr)
+    {
+        free(this->bitmap);
+    }
+}
+
+void Canvas::put_pixel(uint32_t x, uint32_t y, Colour c)
+{
+    uint32_t offset = y * this->stride + x * BytePP;
+    this->bitmap[offset + 0] = MAX(MIN(c.red() * 255, 255), 0);
+    this->bitmap[offset + 1] = MAX(MIN(c.green() * 255, 255), 0);
+    this->bitmap[offset + 2] = MAX(MIN(c.blue() * 255, 255), 0);
+}
+
+Colour Canvas::get_pixel(uint32_t x, uint32_t y)
+{
+    uint32_t offset = y * this->stride + x * BytePP;
+    return Colour(this->bitmap[offset + 0] / 255, this->bitmap[offset + 1] / 255, this->bitmap[offset + 2] / 255);
+}
+
+bool Canvas::SaveAsPNG(const char *filename)
+{
+    uint32_t ret = lodepng_encode24_file(filename, this->bitmap, this->width, this->height);
+
+    if (ret > 0)
+    {
+        printf("lodepng_encode_file returned %d!\n", ret);
+    }
+
+    return ret == 0;
+}

source/include/canvas.h

@@ -0,0 +1,32 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Canvas header
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#ifndef DORAYME_CANVAS_H
+#define DORAYME_CANVAS_H
+
+#include <stdint.h>
+#include <colour.h>
+
+class Canvas
+{
+private:
+    uint8_t *bitmap;
+    uint32_t stride;
+public:
+    uint32_t width, height;
+
+    Canvas(uint32_t width, uint32_t height);
+    ~Canvas();
+
+    void put_pixel(uint32_t x, uint32_t y, Colour c);
+    Colour get_pixel(uint32_t x, uint32_t y);
+
+    bool SaveAsPNG(const char *filename);
+};
+
+#endif /* DORAYME_CANVAS_H */

tests/CMakeLists.txt

@@ -3,7 +3,7 @@ project(DoRayTested)
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 
-set(TESTS_SRC tuples_test.cpp colour_test.cpp)
+set(TESTS_SRC tuples_test.cpp colour_test.cpp canvas_test.cpp)
 
 add_executable(testMyRays)
 target_include_directories(testMyRays PUBLIC ${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})

tests/canvas_test.cpp

@@ -0,0 +1,53 @@
+/*
+ *  DoRayMe - a quick and dirty Raytracer
+ *  Canvas unit tests
+ *
+ *  Created by Manoël Trapier
+ *  Copyright (c) 2020 986-Studio.
+ *
+ */
+#include <colour.h>
+#include <canvas.h>
+#include <math.h>
+#include <gtest/gtest.h>
+
+TEST(CanvasTest, Creating_a_canvas)
+{
+    Canvas c = Canvas(10, 20);
+    int x, y;
+    ASSERT_EQ(c.width, 10);
+    ASSERT_EQ(c.height, 20);
+    for(y = 0; y < 20; y++)
+    {
+        for(x = 0; x < 10; x++)
+        {
+            ASSERT_EQ(c.get_pixel(x, y), Colour(0, 0, 0));
+        }
+    }
+}
+
+TEST(CanvasTest, Test_Writing_pixels_to_a_canvas_Test)
+{
+    Canvas c = Canvas(10, 20);
+    Colour red = Colour(1, 0, 0);
+
+    c.put_pixel(2, 3, red);
+
+    ASSERT_EQ(c.get_pixel(2, 3), red);
+
+}
+
+TEST(CanvasTest, Save_a_PNG_file)
+{
+    Canvas c = Canvas(5, 3);
+    Colour c1 = Colour(1.5, 0, 0);
+    Colour c2 = Colour(0, 0.5, 0);
+    Colour c3 = Colour(-0.5, 0, 1);
+
+    c.put_pixel(0, 0, c1);
+    c.put_pixel(2, 1, c2);
+    c.put_pixel(4, 2, c3);
+
+    ASSERT_TRUE(c.SaveAsPNG("Save_a_PNG_file.png"));
+
+}