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import numpy as np
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
from typing import Protocol
class ImageRenderer:
def __init__(self):
# Setup shader and quad
self.shader = self._init_shader()
self.vao = self._init_quad()
# Get uniform locations from the shader
self.uTransform = glGetUniformLocation(self.shader, "uTransform")
self.uAlpha = glGetUniformLocation(self.shader, "uAlpha")
# Use the shader program and set default texture unit to 0
glUseProgram(self.shader)
glUniform1i(glGetUniformLocation(self.shader, "uTexture"), 0)
# Setup transition
self.transition = None
def set_transition(self, transition_cls):
self.transition = transition_cls(self)
@staticmethod
def compile_shader(source, shader_type):
shader = glCreateShader(shader_type) # Create a new shader object
glShaderSource(shader, source) # Attach the shader source code
glCompileShader(shader) # Compile the shader
if not glGetShaderiv(shader, GL_COMPILE_STATUS): # Check if compilation succeeded
raise RuntimeError(glGetShaderInfoLog(shader).decode()) # Raise error with log if failed
return shader
@staticmethod
def _init_shader():
vertex_src = """
#version 300 es
precision mediump float; // Precision for float variables (mandatory for ES)
layout (location = 0) in vec2 aPos; // Vertex position
layout (location = 1) in vec2 aTexCoord; // Texture coordinates
uniform mat4 uTransform; // Transformation matrix
out vec2 TexCoord; // Output texture coordinate
void main() {
gl_Position = uTransform * vec4(aPos, 0.0, 1.0); // Apply transformation
TexCoord = aTexCoord; // Pass tex coord to fragment shader
}
"""
fragment_src = """
#version 300 es
precision mediump float; // Precision for float variables (mandatory for ES)
in vec2 TexCoord; // Interpolated texture coordinates
out vec4 FragColor; // Final fragment color
uniform sampler2D uTexture; // Texture sampler
uniform float uAlpha; // Global alpha for transparency
void main() {
vec4 texColor = texture(uTexture, TexCoord); // Sample texture
FragColor = vec4(texColor.rgb, texColor.a * uAlpha); // Apply alpha blending
}
"""
# Compile and link shaders into a program
vs = ImageRenderer.compile_shader(vertex_src, GL_VERTEX_SHADER)
fs = ImageRenderer.compile_shader(fragment_src, GL_FRAGMENT_SHADER)
prog = glCreateProgram()
glAttachShader(prog, vs)
glAttachShader(prog, fs)
glLinkProgram(prog)
return prog
@staticmethod
def _init_quad():
# Define a full-screen quad with positions and texture coordinates
quad = np.array([
-1, -1, 0, 0, # Bottom-left
1, -1, 1, 0, # Bottom-right
-1, 1, 0, 1, # Top-left
1, 1, 1, 1, # Top-right
], dtype=np.float32)
# Create and bind a Vertex Array Object
vao = glGenVertexArrays(1)
vbo = glGenBuffers(1)
glBindVertexArray(vao)
glBindBuffer(GL_ARRAY_BUFFER, vbo)
glBufferData(GL_ARRAY_BUFFER, quad.nbytes, quad, GL_STATIC_DRAW)
# Setup vertex attributes: position (location = 0)
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 16, ctypes.c_void_p(0))
glEnableVertexAttribArray(0)
# Setup vertex attributes: texture coordinates (location = 1)
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 16, ctypes.c_void_p(8))
glEnableVertexAttribArray(1)
return vao
def draw_image(self, tex, win_w, win_h, alpha):
if not tex.initialized:
return
glUseProgram(self.shader)
glBindVertexArray(self.vao)
# FIXME check if tex.id is None
glBindTexture(GL_TEXTURE_2D, tex.id)
# Calculate aspect ratios
img_aspect = tex.width / tex.height
win_aspect = win_w / win_h
# Calculate scaling factors to preserve image aspect ratio
if img_aspect > win_aspect:
sx = 1.0
sy = win_aspect / img_aspect
else:
sx = img_aspect / win_aspect
sy = 1.0
# Create transformation matrix for aspect-ratio-correct rendering
transform = np.array([
[sx, 0, 0, 0],
[0, sy, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1],
], dtype=np.float32)
# Pass transformation and alpha to the shader
glUniformMatrix4fv(self.uTransform, 1, GL_FALSE, transform)
glUniform1f(self.uAlpha, alpha)
# Draw the textured quad
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4)
def draw_static(self, tex, win_w, win_h, alpha):
# Set the background color to black
glClearColor(0.0, 0.0, 0.0, 1.0)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
self.draw_image(tex, win_w, win_h, alpha)
glutSwapBuffers()
def draw_transition(self, tex_start, tex_end, win_w, win_h, delta_time, transition_time, transition_duration, reversed):
assert self.transition, "No transition has been set"
# Set the background color to black
glClearColor(0.0, 0.0, 0.0, 1.0)
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
self.transition.draw(tex_start, tex_end, win_w, win_h, delta_time, transition_time, transition_duration, reversed)
glutSwapBuffers()
class Transition(Protocol):
def __init__(self, renderer):
self.renderer = renderer
def draw(self, tex_start, tex_end, win_w, win_h, delta_time, transition_time, transition_duration, reversed):
pass
class TransitionMix(Transition):
def draw(self, tex_start, tex_end, win_w, win_h, delta_time, transition_time, transition_duration, reversed):
# Update alpha value for fade effect
alpha = transition_time / transition_duration
if alpha > 1.0:
alpha = 1.0
# Draw the images on top of one another
self.renderer.draw_image(tex_start, win_w, win_h, 1 - alpha) # TODO instead of decreasing alpha, draw transparent letterboxes
self.renderer.draw_image(tex_end, win_w, win_h, alpha)
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