Kelsidavis-WoWee/src/rendering/lens_flare.cpp

288 lines
8.2 KiB
C++

#include "rendering/lens_flare.hpp"
#include "rendering/camera.hpp"
#include "rendering/shader.hpp"
#include "core/logger.hpp"
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <cmath>
namespace wowee {
namespace rendering {
LensFlare::LensFlare() {
}
LensFlare::~LensFlare() {
cleanup();
}
bool LensFlare::initialize() {
LOG_INFO("Initializing lens flare system");
// Generate flare elements
generateFlareElements();
// Create VAO and VBO for quad rendering
glGenVertexArrays(1, &vao);
glGenBuffers(1, &vbo);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
// Position (x, y) and UV (u, v) for a quad
float quadVertices[] = {
// Pos UV
-0.5f, -0.5f, 0.0f, 0.0f,
0.5f, -0.5f, 1.0f, 0.0f,
0.5f, 0.5f, 1.0f, 1.0f,
-0.5f, -0.5f, 0.0f, 0.0f,
0.5f, 0.5f, 1.0f, 1.0f,
-0.5f, 0.5f, 0.0f, 1.0f
};
glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), quadVertices, GL_STATIC_DRAW);
// Position attribute
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// UV attribute
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float)));
glEnableVertexAttribArray(1);
glBindVertexArray(0);
// Create shader
shader = std::make_unique<Shader>();
// Lens flare vertex shader (2D screen-space rendering)
const char* vertexShaderSource = R"(
#version 330 core
layout (location = 0) in vec2 aPos;
layout (location = 1) in vec2 aUV;
uniform vec2 uPosition; // Screen-space position (-1 to 1)
uniform float uSize; // Size in screen space
uniform float uAspectRatio;
out vec2 TexCoord;
void main() {
// Scale by size and aspect ratio
vec2 scaledPos = aPos * uSize;
scaledPos.x /= uAspectRatio;
// Translate to position
vec2 finalPos = scaledPos + uPosition;
gl_Position = vec4(finalPos, 0.0, 1.0);
TexCoord = aUV;
}
)";
// Lens flare fragment shader (circular gradient)
const char* fragmentShaderSource = R"(
#version 330 core
in vec2 TexCoord;
uniform vec3 uColor;
uniform float uBrightness;
out vec4 FragColor;
void main() {
// Distance from center
vec2 center = vec2(0.5);
float dist = distance(TexCoord, center);
// Circular gradient with soft edges
float alpha = smoothstep(0.5, 0.0, dist);
// Add some variation - brighter in center
float centerGlow = smoothstep(0.5, 0.0, dist * 2.0);
alpha = max(alpha * 0.3, centerGlow);
// Apply brightness
alpha *= uBrightness;
if (alpha < 0.01) {
discard;
}
FragColor = vec4(uColor, alpha);
}
)";
if (!shader->loadFromSource(vertexShaderSource, fragmentShaderSource)) {
LOG_ERROR("Failed to create lens flare shader");
return false;
}
LOG_INFO("Lens flare system initialized: ", flareElements.size(), " elements");
return true;
}
void LensFlare::generateFlareElements() {
flareElements.clear();
// Main sun glow (at sun position)
flareElements.push_back({0.0f, 0.3f, glm::vec3(1.0f, 0.95f, 0.8f), 0.8f});
// Flare ghosts along sun-to-center axis
// These appear at various positions between sun and opposite side
// Bright white ghost near sun
flareElements.push_back({0.2f, 0.08f, glm::vec3(1.0f, 1.0f, 1.0f), 0.5f});
// Blue-tinted ghost
flareElements.push_back({0.4f, 0.15f, glm::vec3(0.3f, 0.5f, 1.0f), 0.4f});
// Small bright spot
flareElements.push_back({0.6f, 0.05f, glm::vec3(1.0f, 0.8f, 0.6f), 0.6f});
// Green-tinted ghost (chromatic aberration)
flareElements.push_back({0.8f, 0.12f, glm::vec3(0.4f, 1.0f, 0.5f), 0.3f});
// Large halo on opposite side
flareElements.push_back({-0.5f, 0.25f, glm::vec3(1.0f, 0.7f, 0.4f), 0.2f});
// Purple ghost far from sun
flareElements.push_back({-0.8f, 0.1f, glm::vec3(0.8f, 0.4f, 1.0f), 0.25f});
// Small red ghost
flareElements.push_back({-1.2f, 0.06f, glm::vec3(1.0f, 0.3f, 0.3f), 0.3f});
}
glm::vec2 LensFlare::worldToScreen(const Camera& camera, const glm::vec3& worldPos) const {
// Transform to clip space
glm::mat4 view = camera.getViewMatrix();
glm::mat4 projection = camera.getProjectionMatrix();
glm::mat4 viewProj = projection * view;
glm::vec4 clipPos = viewProj * glm::vec4(worldPos, 1.0f);
// Perspective divide
if (clipPos.w > 0.0f) {
glm::vec2 ndc = glm::vec2(clipPos.x / clipPos.w, clipPos.y / clipPos.w);
return ndc;
}
// Behind camera
return glm::vec2(10.0f, 10.0f); // Off-screen
}
float LensFlare::calculateSunVisibility(const Camera& camera, const glm::vec3& sunPosition) const {
// Get sun position in screen space
glm::vec2 sunScreen = worldToScreen(camera, sunPosition);
// Check if sun is behind camera
glm::vec3 camPos = camera.getPosition();
glm::vec3 camForward = camera.getForward();
glm::vec3 toSun = glm::normalize(sunPosition - camPos);
float dotProduct = glm::dot(camForward, toSun);
if (dotProduct < 0.0f) {
return 0.0f; // Sun is behind camera
}
// Check if sun is outside screen bounds (with some margin)
if (std::abs(sunScreen.x) > 1.5f || std::abs(sunScreen.y) > 1.5f) {
return 0.0f;
}
// Fade based on angle (stronger when looking directly at sun)
float angleFactor = glm::smoothstep(0.3f, 1.0f, dotProduct);
// Fade at screen edges
float edgeFade = 1.0f;
if (std::abs(sunScreen.x) > 0.8f) {
edgeFade *= glm::smoothstep(1.2f, 0.8f, std::abs(sunScreen.x));
}
if (std::abs(sunScreen.y) > 0.8f) {
edgeFade *= glm::smoothstep(1.2f, 0.8f, std::abs(sunScreen.y));
}
return angleFactor * edgeFade;
}
void LensFlare::render(const Camera& camera, const glm::vec3& sunPosition, float timeOfDay) {
if (!enabled || !shader) {
return;
}
// Only render lens flare during daytime (when sun is visible)
if (timeOfDay < 5.0f || timeOfDay > 19.0f) {
return;
}
// Calculate sun visibility
float visibility = calculateSunVisibility(camera, sunPosition);
if (visibility < 0.01f) {
return;
}
// Get sun screen position
glm::vec2 sunScreen = worldToScreen(camera, sunPosition);
glm::vec2 screenCenter(0.0f, 0.0f);
// Vector from sun to screen center
glm::vec2 sunToCenter = screenCenter - sunScreen;
// Enable additive blending for flare effect
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE); // Additive blending
// Disable depth test (render on top)
glDisable(GL_DEPTH_TEST);
shader->use();
// Set aspect ratio
float aspectRatio = camera.getAspectRatio();
shader->setUniform("uAspectRatio", aspectRatio);
glBindVertexArray(vao);
// Render each flare element
for (const auto& element : flareElements) {
// Calculate position along sun-to-center axis
glm::vec2 position = sunScreen + sunToCenter * element.position;
// Set uniforms
shader->setUniform("uPosition", position);
shader->setUniform("uSize", element.size);
shader->setUniform("uColor", element.color);
// Apply visibility and intensity
float brightness = element.brightness * visibility * intensityMultiplier;
shader->setUniform("uBrightness", brightness);
// Render quad
glDrawArrays(GL_TRIANGLES, 0, VERTICES_PER_QUAD);
}
glBindVertexArray(0);
// Restore state
glEnable(GL_DEPTH_TEST);
glDisable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // Restore standard blending
}
void LensFlare::setIntensity(float intensity) {
this->intensityMultiplier = glm::clamp(intensity, 0.0f, 2.0f);
}
void LensFlare::cleanup() {
if (vao) {
glDeleteVertexArrays(1, &vao);
vao = 0;
}
if (vbo) {
glDeleteBuffers(1, &vbo);
vbo = 0;
}
}
} // namespace rendering
} // namespace wowee