precision highp float; uniform vec2 resolution; uniform float time; uniform vec2 mouse; uniform sampler2D backbuffer; uniform sampler2D channel0; uniform vec2 channelSize0; // ------------------ Card IO Module ------------------ // // The MIT License // Copyright © 2020 IWBTShyGuy const int MAX_ROW = 255; const int BUFFER_LENGTH = 100; const vec4 BLACK = vec4(0, 0, 0, 1); const vec4 WHITE = vec4(1); // Returns the pixel on the image is on the letter or not. // This function is depends on the letter image. bool onLetter(in vec2 uv) { vec4 col = texture2D(channel0, uv); return col.x > 0.7 && col.y > 0.7; } bool inUnitSquare(in vec2 uv) { return abs(uv.x - 0.5) <= 0.5 && abs(uv.y - 0.5) <= 0.5; } vec4 searchRows(in vec2 uv) { if (inUnitSquare(uv)) { return texture2D(channel0, (uv + 0.01) / 1.02); } else if (uv.x < 1.0) { return BLACK; } else { float dt = 1.0 / channelSize0.x; for (int i = 0; i < 2048; i++) { float x = dt * float(i); if (x > 1.0) break; if (onLetter(vec2(x, uv.y))) return WHITE; } return BLACK; } } vec2 getRowRange(in int row) { vec2 res; bool prevOnRow = false; float dt = 1.0 / channelSize0.y; for (int i = 0; i < 2048; i++) { float y = 1.0 - float(i) * dt; if (y < 0.0) break; vec2 st = vec2(0.995, (y + 0.01) / 1.02); bool onRow = texture2D(backbuffer, st).x > 0.5; if (!prevOnRow && onRow) res.x = y; if (prevOnRow && !onRow) { res.y = y; if (row == 0) return res; else row -= 1; } prevOnRow = onRow; } return vec2(0); } int readCounter() { float score = texture2D(backbuffer, vec2(0.005)).x; return int(score * float(MAX_ROW)); } vec4 searchLetters(in vec2 uv, in int row) { vec2 st = (uv + 0.01) / 1.02; if (uv.y < 1.0) return texture2D(backbuffer, st); if (uv.x > 1.0) return BLACK; vec2 range = getRowRange(row); if (range.x == range.y) return BLACK; float dt = 1.0 / channelSize0.y; for (int i = 0; i < 2048; i++) { float y = range.x - float(i) * dt; if (y < range.y) break; if (onLetter(vec2(st.x, y))) return WHITE; } return BLACK; } int getBufferHead() { for (int i = 0; i < BUFFER_LENGTH; i++) { float x = (float(i) + 0.5) / float(BUFFER_LENGTH); vec2 st = vec2((x + 0.01) / 1.02, 0.005); float score = texture2D(backbuffer, st).y; if (score == 0.0) return i; } return BUFFER_LENGTH; } vec2 getLetterRange(in int cursor) { vec2 res; bool prevOnRow = false; float dt = 1.0 / channelSize0.x; for (int i = 0; i < 2048; i++) { float x = float(i) * dt; if (x > 1.0) break; vec2 st = vec2(x, 0.995); bool onRow = texture2D(backbuffer, st).x > 0.5; if (!prevOnRow && onRow) res.x = x; if (prevOnRow && !onRow) { res.y = x; if (cursor == 0) return res; else cursor -= 1; } prevOnRow = onRow; } return vec2(0); } vec4 getLetters(in vec2 uv, in int row) { vec4 col = texture2D(backbuffer, (uv + 0.01) / 1.02); if (uv.y > 0.0) return col; if (uv.x < 0.0) return BLACK; if (col.x != 0.0) return col; vec2 row_range = getRowRange(row); int offset = getBufferHead(); int cursor = int(uv.x * float(BUFFER_LENGTH)); vec2 range = getLetterRange(cursor - offset); if (range.y == 0.0) return BLACK; return vec4(row_range, range); } vec4 readLetters(in vec2 uv) { if (uv.x < 0.0 && uv.y < 1.0) { return texture2D(backbuffer, vec2(0.005)) + 1.0 / 255.0; } int k = readCounter(); int row = k / 2; if (k - k / 2 * 2 == 0) return searchLetters(uv, row); else return getLetters(uv, row); } vec4 readBuffer(in int idx) { float x = (float(idx) + 0.5) / float(BUFFER_LENGTH); return texture2D(backbuffer, vec2((x + 0.01) / 1.02, 0.005)); } struct Card { vec2 origin; vec2 size; }; Card readCard(in int idx) { vec4 info = readBuffer(idx); Card card; card.origin = vec2(info.z, info.y); card.size = vec2(info.w - info.z, info.x - info.y); return card; } vec4 printCard(in Card card, in vec2 uv) { vec2 pixel = card.size * channelSize0; float asp = pixel.y / pixel.x; uv.x = asp * (uv.x - 0.5) + 0.5; if (!inUnitSquare(uv)) return BLACK; vec2 st = card.origin + uv * card.size; if (onLetter(st)) return WHITE; else return BLACK; } // ------------------ Main ------------------ // // Attribution 4.0 International (CC BY 4.0) // Copyright © 2020 IWBTShyGuy const float RADIUS = 0.4; const float LETTER_SIZE = 0.1; const float PI = 3.141592653; void main() { vec2 uv = 1.02 * gl_FragCoord.xy / resolution.xy - 0.01; if (time < 3.0) { gl_FragColor = texture2D(channel0, (uv + 0.01) / 1.02); return; } else if (time < 3.5) { gl_FragColor = searchRows(uv); return; } else if (time < 4.0) { gl_FragColor = readLetters(uv); return; } else if (uv.y < 0.0) { gl_FragColor = texture2D(backbuffer, (uv + 0.01) / 1.02); return; } int nLetters = getBufferHead(); uv = (uv + 0.01) / 1.02; uv = (uv - 0.5) * vec2(resolution.x / resolution.y, 1) + 0.5; for (int i = 0; i < 100; i++) { if (i == nLetters) break; Card card = readCard(i); float theta = time - 4.0 - float(i) / float(nLetters) * 2.0 * PI; theta = mix(0.0, theta, clamp(time - 4.0, 0.0, 1.0)); mat2 rot = mat2(cos(theta), -sin(theta), sin(theta), cos(theta)); vec2 st = rot * (uv - 0.5); st.y -= RADIUS; st /= LETTER_SIZE; st += 0.5; st = mix((uv - card.origin) / LETTER_SIZE, st, clamp(time - 4.0, 0.0, 1.0)); gl_FragColor = max(gl_FragColor, printCard(card, st)); } }

Read Letters Circle